Stimulation of the synthesis of the activity of an isoform of lysl oxidase-like loxl for stimulating the formation of elastic fibres

ABSTRACT

The invention relates to the stimulation of the synthesis and of the activity of an isoform of lysyl oxidase, and more particularly of the LOXL (lysyl oxidase-like) isoform. 
     The invention relates notably to a method of identifying an active principle which stimulates the formation of elastic fibers. 
     The aim of the invention is mainly to provide such a method of identification so as to provide compositions which enable stimulating the formation of elastic fibers.

The invention relates to the stimulation of the activity of an isoformof lysyl oxidase, and more particularly of the LOXL (lysyl oxidase-like)isoform.

STATE OF THE ART

The properties of resistance and of elasticity of the skin and of themucous membranes are essentially defined by the collagen fibers andelastin fibers of the dermis. Elastin is a protein which makes up theelastic fibers by combining itself with other molecules such asfibrillins and MAGPs (Microfibrillar Associated Glycoproteins).

The elastic fibers are formed of elastin deposited on the microfibrils.Elastin is synthesized in the form of soluble tropoelastin whichacquires its physico-chemical properties (insolubility, elasticity)after the intra- and inter-molecular cross-linking of it by a lysyloxidase, and its deposit on the microfibrils. The elastic fibers areresponsible for the elastic property of the organs which contain them(vessels, pulmonary parenchyma, elastic cartilages, skin . . . ). Theelastic fibers are mainly constituted of elastin deposited on themicrofibrils. The name <<elastin>> was reserved to the protein whichforms the amorphous portion of the elastic fibers and which impartedtheir elasticity to them. Recently, components of these elastic fibershave been shown in the epidermis.

The collagen fibrils are formed by the trimeric assembly of chains ofcollagen. These collagen fibers are also cross-linked by a lysyloxidase.

Ageing of skins and of mucous membranes is associated with amodification of these fibrillar networks, notably that of the elasticfibers which degrade and which do not re-form correctly. Similarly, inscars, the network of elastic fibers does not form correctly. Five knownisoforms exist in the family of lysyl oxidases (LOs): LOX, LOXL, LOXL2,LOXL3, LOXL4 (Csiszar, Lysyl oxidases: A novel multifunctional amineoxidase family, Nucleic Acid Research and Molecular Biology, 2001, vol70, p2-28). LOX is clearly involved in the cross-linking of collagenfibers (Seve et al., Expression analysis of recombinant lysyl oxidase(LOX) in myofibroblast-like cells, Connective Tissue Research, 2002, 43:613-619).

Functional elastic fibers (which are mainly found in the skin, thevessels, the macula of the retina and the inter-vertebral discs) areformed during prenatal development and immediately after birth. In theskin, these elastic fibers are formed by the fibroblasts of the dermis,but certain compounds, which are necessary for the elaboration of theelastic fibers, have also been found in the cells of the epidermis. Thecollagen fibers are synthesized in the connective tissues throughout thewhole life.

The rate of replacement of the elastic fibers is very low in adult life,although the overall level of elastin of the skin can increase (Ashcroftet al., Age-related changes in the temporal and spatial distributions offibrillin and elastin mRNAs and proteins in acute cutaneous wounds ofhealthy humans, J. Pathol., 1997, 183: 80-89). In the newly-born, themicrofibrils are not all completely covered with elastin, and become sotowards puberty. At 40 years, inclusions are seen to appear on thefibers, more frequently in women, and then the fragmentation of theelastic fibers and their disappearance under the dermal-epidermaljunction (DEJ). This fractioning and/or this disappearance under the DEJmanifests itself by a loss of elasticity of the skin and the formationof wrinkles. The synthesis of non-functional elastic fibers is observedduring photo-ageing, but this increase is accompanied with anaccelerated loss of the elastic fibers under the DEJ. (Watson et al.,Fibrillin-rich microfibrils are reduced in photo-aged skin. Distributionat the dermal-epidermal junction, J. Invest. Dermatol., 1999, 112:782-787).

Furthermore, the neosynthesis of elastic fibers is carried out little inthe scars of adult persons, while paradoxically, this property be inpart found again in aged persons (more than 70 years old) whose elasticfibers produced are very fragmented. Yet the main components whichintervene in the final composition of the elastic fibers are present(elastin, microfibrils) and the overall lysyl oxidase activity ismaintained (Pasquali-Ronchetti and Baccarani-Contri, Elastic fiberduring development and aging, Microscopy Res. Tech., 1997, 38: 428-435).This suggested to the inventors that one or more factors were missingwhich enable the formation of functional elastic fibers in the adult,but which exist during embryonic development and during the first age.

The prior art does not enable providing criteria which enable evaluatingthe impact of an active principle in dermato-cosmetology on a functionalneo-elastogenesis. In this context, it is also very difficult to obtainobjective criteria enabling the impact of these actives to be judged.The screening methods of actual active principles bear upon theevaluation of the expression of the genes involved in the formation ofthe elastic fibers, such as elastin or the fibrillins.

Furthermore, at the present time, animal experimentation is forbidden incosmetics in Europe and human experimentation is ethically disputed. Itis therefore unacceptable to the inventors to carry out a screeningmethod, for cosmetic applications, which makes use of animals or humanbeings.

In three-dimensional models, such as Mimeskin® (Coletica, Lyons,France), keratinocytes induce the synthesis of tropoelastin and thedeposit of tropoelastin on the microfibrils (Duplan-Perrat et al.,Keratinocytes influence the maturation and organization of the elastinnetwork in a skin equivalent. J. Invest. Dermatol. 114: 365-70, 1999).In the Mimeskin® model, the extracellular matrix showed anultra-structural organization similar to that of the skin, with thecollagen being organized in rays and elastic fibers which areconstituted of elastin deposited on the microfibrils. This model hasalso been used for testing the effectiveness of certain molecules, suchas inhibitors of lysyl oxidases. This has enabled proving that theinhibition of the lysyl oxidases induced a disorganization of thecollagen fibers and the elastin fibers, but also a deviation from theprogram of differentiation of the keratinocytes, with a reduction of thelevel of expression of the labels of terminal differentiation, such asfilaggrin (Farjanel et al., French patent 01 10443, CNRS, Use ofinhibitors of lysyl oxidases for cell culture and tissue engineering(<<Utilisation d'inhibiteurs des lysyl oxydases pour la culturecellulaire and le genie tissulaire>>). In that patent, no distinction ismade between the different isoforms of LO.

However, those studies did not enable developing a method of identifyingactive principles which enable stimulating the formation of functionalelastic fibers.

The prior art does not therefore enable providing active principleswhich enable stimulating the formation of functional elastic fibers.

Furthermore, the prior art does not enable a dynamic tracking of thezone of expression of the isoform of the lysyl oxidase LOXL, notably dueto the fact that the methods provided by the prior art are imprecise.

AIMS OF THE INVENTION

The aim of the invention is mainly to solve the technical problems setforth above and notably the technical problem aiming to provide a methodof identifying active principles which stimulate the formation offunctional elastic fibers. By “functional elastic fibers” is meant theusual meaning in the art as described above and notably in the contextof the invention, elastic fibers which have elastic properties comingfrom a tridimensional structure.

The invention also relates to the use of the L isoform of lysyl oxidaseor of an active principle which stimulates the enzymatic activity or theexpression of the L isoform of lysyl oxidase (LOXL), notably forstimulating the formation of functional elastic fibers.

The invention enables solving the technical problem consisting ofproviding a method of locating the expression of LOXL and of trackingthis expression.

SUMMARY OF THE INVENTION

In this text, by the term “LOXL”, or “hLOXL”, the inventors mean the Lisoform of the human lysyl oxidase protein LOXL.

In this text, by the term “LOX”, or “hLOX”, the inventors mean theinitial isoform of the human lysyl oxidase protein LOX.

By “stimulating the expression of the isoform of the lysyl oxidaseLOXL”, the inventors mean the stimulation of the expression of the geneencoding LOXL or of its promoter, and notably the stimulation of thesynthesis of the messenger RNA encoding LOXL, but also the stimulationof the synthesis of LOXL from this messenger RNA.

By “stimulating the expression of elastin”, the inventors mean thestimulation of the expression of the gene encoding the elastin proteinor of its promoter, and notably the stimulation of the synthesis of themessenger RNA encoding the elastin protein, but also the stimulation ofthe synthesis of the protein elastin or of its precursor, tropoelastin,from this messenger RNA.

In this invention, the inventors thus aim to stimulate mainly either theexpression of LOXL as described, or the enzymatic activity of LOXL.

This stimulation must be effective enough to enable stimulating theformation of functional elastic fibers.

Active principles are considered as effective which enable obtaining anactivation or an increase of about 1.5 times the expression and/or theactivity of LOXL on a model, which comprises at least one cell typewhich presents an expression and/or an activity of LOXL, upon contact ofthese active principles, with respect to the level of expression and/orof activity of LOXL in a control model (without placing the activeprinciples in contact).

It is such that the present invention relates, according to a firstaspect, to the use of the <<like>> isoform of lysyl oxidase having theSequence ID No 1, also called LOXL, or of an homologous or essentiallyhomologous form thereof, or of a substance which promotes the activityand/or the expression of LOXL, for the manufacture of a composition forstimulating the formation of elastic fibers.

By “an homologous or essentially homologous form thereof” it is meant anhomologous form of the isoform of lysyl oxidase LOXL which has the sameor similar activity as LOXL as defined herein.

Advantageously, the expression of LOXL is either the expression of asequence of nucleotides encoding LOXL or the expression of a sequence ofpeptides constituting a fraction of the protein LOXL, said sequence ofpeptides being preferably selected from the Sequence ID No 1.

Advantageously, said composition is a cosmetic, neutraceutical, medicalor pharmaceutical composition.

Advantageously, the composition further comprises a second substancewhich stimulates the expression of the protein elastin, notably forstimulating the formation of elastic fibers, said second substancepreferably being the substance which promotes the activity and/or theexpression of LOXL.

Advantageously, said active substance comprises a region which fixes toat least one part of the sequence of nucleotides of the promoter of thehuman LOXL gene (Pr) (SEQ ID No 3) or of an homologous or essentiallyhomologous form thereof, or modulates the expression of a protein whichfixes to at least one part of the sequence of nucleotides of thepromoter of the human LOXL gene (Pr) (SEQ ID No 3) or of an homologousor essentially homologous form thereof. This sequence is given from thenucleotide −2630 before the ATG codon, and the nucleotides from −2172 to−1 have in particular been studied.

Advantageously, the active substance is selected from the groupconsisting of dill, currant, cardamon, black radish, box holly,cinnamon, lactic bacteria-based fermentations, oats, potato, silk, Asafoetida gum, ethyl hexenoate and its derivatives, methyl butyrate andits derivatives, and ethyl decadienoate and its derivatives.

Advantageously, the use described above is carried out for inducing aneo-elastogenesis of the tissues, and notably for stimulating theelasticity of the tissues thus obtained, and for reducing skin wrinkles.

Advantageously, the use described above is carried out for combatingagainst the loosening of the tissues, notably when the loosening of thetissues is observed during ageing or during solar exposures, fordensifying the extracellular matrix, for firming up the subcutaneoustissues, for reducing skin wrinkles, for exerting an anti-wrinkleseffect, for improving the quality of scar tissue and the appearance ofscars, notably dystrophic and keloid scars, or for combating againststretch marks.

According to a second aspect, the invention relates to a cosmeticcomposition which comprises an active substance as defined above,optionally in a mixture with a cosmetically acceptable excipient.

According to a third aspect, the invention relates to a neutraceuticalcomposition which comprises an active substance as defined above,optionally in a mixture with an excipient acceptable for food.

According to a fourth aspect, the invention relates to a pharmaceuticalcomposition which comprises an active substance as defined above,optionally in a mixture with a pharmaceutically acceptable excipient.

For the cosmetic or pharmaceutical compositions, the excipient containsfor example at least one compound selected from the group consisting ofpreservatives, emollients, emulsifiers, surfactants, moisturizers,thickeners, conditioners, matifying agents, stabilizers, antioxidants,texture agents, brightening agents, filmogenic agents, solubilisers,pigments, dyes, perfumes and solar filters. These excipients arepreferably selected from the group consisting of amino acids and theirderivatives, polyglycerols, esters, polymers and derivatives ofcellulose, lanolin derivatives, phospholipids, lactoferrins,lactoperoxidases, sucrose-based stabilisers, E vitamins and itsderivatives, natural and synthetic waxes, plant oils, triglycerides,insaponifiables, phytosterols, plant esters, silicones and itsderivatives, protein hydrolysates, jojoba oil and its derivatives,lipo/hydrosoluble esters, betaines, aminoxides, plant extracts, estersof sucrose, titanium dioxides, glycines, and parabens, and morepreferably from the group consisting of butylene glycol, steareth-2,steareth-21, glycol-15 stearyl ether, cetearyl alcohol, phenoxyethanol,methylparaben, ethylparaben, propylparaben, butylparaben, butyleneglycol, natural tocopherols, glycerol, sodium dihydroxycetyl, isopropylhydroxycetyl ether, glycol stearate, triisononaoine, octyl cocoate,polyacrylamide, isoparaffin, laureth-7, a carbomer, propylene glycol,glycerol, bisabolol, dimethicone, sodium hydroxide, PEG30-dipolyhydroxysterate, capric/caprylic triglycerides, cetearyloctanoate, dibutyl adipate, grape seed oil, jojoba oil, magnesiumsulphate, EDTA, cyclomethicone, xanthan gum, citric acid, sodium laurylsulphate, mineral waxes and oils, isostearyl isostearate, propyleneglycol dipelargonate, propylene glycol isostearate, PEG 8 Beeswax,hydrogenated palm tree heart oil glycerides, hydrogenated palm oilglycerides, lanolin oil, sesame oil, cetyl lactate, lanolin alcohol,castor oil, titanium dioxide, lactose, sucrose, low densitypolyethylene, and an isotonic saline solution.

Advantageously, the compositions cited above are formulated in a formselected from the group consisting of a solution, which is aqueous oroily, an aqueous cream or gel or an oily gel, notably in a pot or in atube, notably a shower gel, a shampoo; a milk; an emulsion, amicroemulsion or a nanoemulsion, notably an oil-in-water or water-in-oilor multiple or silicone-containing microemulsion or nanoemulsion; alotion, notably in a glass bottle, a plastic bottle or in a measurebottle or in an aerosol; an ampoule; a liquid soap; a dermatologicalbar; an ointment; a foam; an anhydrous product, preferably a liquid,pasty or solid anhydrous product, e.g. in the form of a stick, notablyin the form of a lipstick.

Advantageously, the compositions which are sufficiently liquid can beadministered, notably via the parenteral, ocular, pulmonary, oral ornasal route.

Advantageously, the pasty or dry compositions (pastes, powders, tablets,capsules, granules, suppositories . . . ), can be introduced into thebody notably via the oral, sublingual, nasal or rectal route.

Advantageously, when the formulation of the composition allows it, theadministration route is cutaneous or transmucosal, notably byapplication of the composition on the skin or on a mucous membrane.

Advantageously, from the various formulations and routes ofadministration, the person skilled in the art will select the one whichis adequate for the effectiveness sought after.

According to a fifth aspect, the invention relates to a method ofcosmetic care characterized, in that it comprises the use of acomposition described above.

Advantageously, the cosmetic care is selected from the group consistingof combating against the loosening of the tissues, notably when theloosening of the tissues is observed during ageing or during solarexposures, densifying the extracellular matrix, firming up thesubcutaneous tissues, reducing skin wrinkles, anti-wrinkles effects,improving the quality of scar tissue and the appearance of scars,notably dystrophic and keloid scars, and combating against stretchmarks.

According to a sixth aspect, the invention relates to a screening methodof a substance which promotes the activity of LOXL or of an homologousor essentially homologous form thereof, for stimulating the formation ofelastic fibers, characterized in that it comprises:

-   -   placing a potentially active substance in contact with LOXL at        least one type of cells capable of expressing the isoform LOXL        or of an homologous or essentially homologous form thereof, and    -   a) analyzing the activity of LOXL or of an homologous or        essentially homologous form thereof, notably with the aim of        identifying whether said potentially active substance stimulates        the activity of LOXL or of an homologous or essentially        homologous form thereof, or    -   b) analyzing the expression of LOXL or of an homologous or        essentially homologous form thereof, notably with the aim of        identifying whether said potentially active substance stimulates        the expression of LOXL or of an homologous or essentially        homologous form thereof.

Within the context of analyzing the expression of LOXL or of anhomologous or essentially homologous form thereof:

Advantageously, it is sought whether said potentially active substancestimulates:

-   -   the expression of at least one sequence of nucleotides encoding        the protein LOXL or of an homologous or essentially homologous        form thereof, and/or    -   the expression of a sequence of peptides essentially        constituting a peptide fraction of the protein LOXL or of an        homologous or essentially homologous form thereof.

Advantageously, the analysis of the expression of LOXL is carried out byqualitative and/or quantitative analysis of the expression of at leastone part of a sequence of nucleotides encoding LOXL.

Advantageously, the sequence of nucleotides is the cDNA which iscomplementary to the mRNA encoding LOXL, the LOXL cDNA being defined bythe sequence ID No 2.

Advantageously, the analysis of the expression of LOXL makes use of areverse transcription polymerase chain reaction (RT-PCR) which comprisesthe use of primers which hybridize with at least one part of thesequence of nucleotides of the complementary DNA encoding LOXL (SEQ IDNo 2), in order to amplify at least one part of the sequence ofnucleotides encoding the LOXL.

Advantageously, the method also comprises a step locating the expressionof LOXL which is carried out on a reconstructed skin model or on a amodel based on biopsies:

-   -   by in situ hybridization, notably of at least one part of a        sequence of nucleotides encoding LOXL for example by using at        least one DNA probe which hybridizes with at least one part of        the sequence of nucleotides of the complementary DNA encoding        LOXL (SEQ ID No 2); or    -   by immuno-detection notably by using at least one specific        antibody of the LOXL.

The specific antibodies are itemized in Example 1.

Advantageously, the screening method comprises the comparison of theexpression of LOXL with the expression of LOXL expressed in a controlwhich does not comprise said potentially active substance.

Advantageously, the living cells comprise fibroblasts, originatingnotably from normal human skin, such as, for example, originating fromthe foreskin or from a skin of an adult subject.

Advantageously, the living cells comprise epithelial cells, for examplekeratinocytes, originating notably from normal human skin, such as, forexample, originating from the foreskin or from a skin of an adultsubject.

Advantageously, the living cells originate from at least one skin havinga particular localization, for example from the face, from the abdomen,or from the breasts, and being able to be characterized as being<<aged>> or as being <<exposed>> to sun's radiation or not, or from askin originating from a zone which has scars or stretch marks.

Advantageously, the screening method makes use of a reconstructed skinmodel, preferably at least one dermis model which comprises fibroblasts,or a model based on biopsies.

Advantageously, the screening method makes use of a reconstructed skinmodel or a model based on biopsies. The reconstructed skin model used isadvantageously the Mimeskin® reconstructed skin model but may also be amodel of connective matrix, of epidermis or of epithelium, or ofreconstructed skin or mucous membrane:

1) The three-dimensional connective matrix (dermis or chorion) culturemodel, comprises a support which is sown with stromal cells in order toform reconstructed dermis or reconstructed chorions. This support ispreferably selected from:

-   -   an inert support selected from the group consisting of a        semi-permeable synthetic membrane, in particular a        semi-permeable nitrocellulose membrane, a semi-permeable nylon        membrane, a Teflon membrane or a Teflon sponge, a semi-permeable        membrane of polycarbonate or polyethylene, polypropylene, or of        polyethylene terephthalate (PET), a semi-permeable Anopore        inorganic membrane, of cellulose acetate or cellulose ester        (HATF) membrane, a semi-permeable Biopore-CM membrane, a        semi-permeable polyester membrane, a membrane or a film of        polyglycolic acid. In this group; the dermal models Skin²™ model        ZK1100 and Dermagraft® and Transcyte® (Advanced Tissue Sciences)        for example, are found;    -   a cell culture-treated plastic (formation of a dermal leaf:        Michel M. et al. in In Vitro Cell. Dev Biol. -Animal (1999) 35:        318-326);    -   a gel or a membrane based on hyaluronic acid (Hyalograft®        3D-Fidia Advanced Biopolymers) and/or on collagen and/or on        fibronectin and/or on fibrin; in this group, dermal model        Vitrix® (Organogenesis) for example is found;    -   a porous matrix; which is surfaced or non-surfaced, made from        collagen being able to contain one or more glycosaminoglycans        and/or eventually chitosan (EP 0 296 078 A1 of the CNRS, WO        01/911821 and WO 01/92322 of Coletica).

2) The Three-Dimensional Epidermis or Epithelium Culture Model

Comprises a support which is sown or not beforehand with stromal cells,particularly fibroblasts, and then with epithelial cells and inparticular keratinocytes, so as to obtain reconstructed epithelia orepidermis. This support is preferably selected from:

-   -   an inert support selected from the group consisting of a        semi-permeable synthetic membrane, in particular a        semi-permeable nitrocellulose membrane, a semi-permeable nylon        membrane, a Teflon membrane or a Teflon sponge, a semi-permeable        membrane of polycarbonate or polyethylene, polypropylene, or of        polyethylene terephthalate (PET), a semi-permeable Anopore        inorganic membrane, of cellulose acetate or cellulose ester        (HATF) membrane, a semi-permeable Biopore-CM membrane, a        semi-permeable polyester membrane; in this group, the        reconstructed models Epiderm and Epithelia (Skinethic®) are        found, as well as the models EpiDerm®, EpiAirway®, EpiOccular®        (Mattek Corporation);    -   a film or a membrane based on hyaluronic acid and/or on collagen        and/or on fibronectin and/or on fibrin. In this group, the        models: Episkin® (L'Oreal) and Laserskin® (Fidia advanced        Biopolymers), in particular, can be cited.

3) The Three-Dimensional Reconstructed Skin or Mucous Membrane CultureModel

Comprises a matrix support (dermal or of chorion) which is sown withepithelial cells so as to obtain a reconstructed mucous membrane or withkeratinocytes so as to obtain a reconstructed skin. This support ispreferably selected from:

-   -   an inert support selected from the group consisting of a        semi-permeable synthetic membrane, in particular a        semi-permeable nitrocellulose membrane, a semi-permeable nylon        membrane, a Teflon membrane or a Teflon sponge, a semi-permeable        membrane of polycarbonate or polyethylene, polypropylene, or of        polyethylene terephthalate (PET), a semi-permeable Anopore        inorganic membrane, of cellulose acetate or cellulose ester        (HATF) membrane, a semi-permeable Biopore-CM membrane, a        semi-permeable polyester membrane, said inert support containing        stromal cells, in particular fibroblasts,    -   a gel based on collagen and/or hyaluronic acid and/or        fibronectin, and/or on fibrin comprising stromal cells, in        particular fibroblasts,    -   a porous matrix, which is surfaced or non-surfaced, made from        collagen being able to contain one or more glycosaminoglycans        and/or eventually chitosan, these porous matrices integrating        stromal cells, in particular, fibroblasts,    -   a human or animal de-epidermisised dermis or dead dermis.

In this group, the models Apligraf®Organogenesis), ATS-2000(CellSystems® Biotechnologie Vertrieb), as well as Skin²™(ZK1200-1300-2000-Advanced Tissue Science), in particular, can be cited.

Furthermore, models exist which are dedicated to tissue therapy andwhich can also be the subject of such studies. The models Epidex™ (ModexThérapeutiques), Epibase® (Laboratoire Genevrier), Epicell™ (Genzyme),Autoderm™ and Transderm™ (Innogenetics), can be cited.

Advantageously, the screening method makes use of a reconstructed skinmodel, preferably at least one epidermis model which compriseskeratinocytes.

Advantageously, the method comprises a step of analyzing the expressionof a sequence at least of the protein elastin and/or tropoelastin, or ofa sequence of nucleotides encoding the protein elastin, notably fordetecting an eventual stimulation of the expression of the proteinelastin when said active substance is in contact with said living cells.

Advantageously, the method comprises a step of immuno-detecting theexpression of the protein LOXL, notably with the aim of performing thetraceability of neo-elastogenesis, notably in the epithelial tissuesand/or in the connective tissues, said tissues originating from at leastone reconstructed skin model or from a model based on biopsies.

Advantageously, said active substance is selected from the groupconsisting of dill, currant, cardamon, black radish, box holly,cinnamon, lactic bacteria-based fermentations, oats, potato, silk, Mafoetida gum, ethyl hexenoate and its derivatives, methyl butyrate andits derivatives, and ethyl decadienoate and its derivatives.

According to a seventh aspect, the invention relates to a method oflocating the expression of LOXL or of an homologous or essentiallyhomologous form thereof in tissues with the aim of performing thetraceability of neo-elastogenesis, notably in connective tissues, saidtissues originating from at least one reconstructed skin model or frombiopsies, characterized in that the method comprises a step ofimmuno-detecting the protein LOXL or of an homologous or essentiallyhomologous form thereof or of in situ hybridizing at least one part of asequence of nucleotides encoding LOXL or of an homologous or essentiallyhomologous form thereof.

The invention also relates to a method of locating the expression ofLOXL in tissues with the aim of performing the traceability ofneo-elastogenesis, notably in epithelial tissues and/or in connectivetissues, characterized in that the method comprises a step ofimmuno-detecting the protein LOXL or of in situ hybridizing the geneencoding LOXL.

The invention also relates to the use of an active principle whichmodifies the enzymatic activity or the expression of the protein LOXLfor stimulating the formation of elastic fibers.

The invention also relates to a method of treatment of a deficiencyassociated with the enzymatic activity of the isoform of the proteinlysyl oxidase LOXL which comprises administering, to a subject, atherapeutically effective amount of a composition which comprises theprotein lysyl oxidase LOXL, or of an homologous or essentiallyhomologous form thereof, or a compound which stimulates the enzymaticactivity or the expression of the protein lysyl oxidase LOXL.

Advantageously, this method of treatment enables performing a treatmentselected from combating against the loosening of the tissues, notablywhen the loosening of the tissues is observed during ageing or duringsolar exposures, densifying the extracellular matrix, firming up thesubcutaneous tissues, reducing skin wrinkles, anti-wrinkles effects,improving the quality of scar tissue and the appearance of scars,notably of dystrophic scars, in particular dystrophic scars, and keloidscars, and combating against stretch marks.

DETAILED DESCRIPTION OF THE INVENTION

The inventors have unexpectedly demonstrated that the activity of LOXLwas a main missing link in elastogenesis in the adult and that it waspossible to reactivate the synthesis of this isoform of lysyl oxidase soas to obtain a stimulating effect on elastogenesis.

The inventors have in fact demonstrated that this isoform of the familyof lysyl oxidases (LO) is associated with elastogenesis in areconstructed skin model producing elastic fibers. In seeking whetherthis isoform was present or absent in the skin of various ages andduring skin alterations, the inventors noticed the simultaneous presenceor absence of this isoform and of elastogenesis, and this enablesindicating that the activity of this isoform of LO corresponds to amissing link the synthesis of which it is necessary to modulate in orderto orchestrate a functional elastogenesis.

The inventors have thus developed a method which enables visualizingincreased expressions of this isoform of LO (LOXL), and then have soughtactive principles, notably amongst plant extracts or chemical molecules,which in particular stimulate the expression of the mRNAs encoding LOXL.The actives selected were then incorporated in cosmetic,dermo-pharmaceutical and pharmaceutical compositions in particular, forapplications in the combat against loosening of the tissues duringageing, as well as in the improvement of the quality of scar tissue andthe appearance of scars and stretch marks.

The inventors have developed specific antibodies of the mature LOXLforms (vide Examples 1 and 2), and have demonstrated in this way thatthe absence of this lysyl oxidase isoform is correlated to the problemsof the synthesis of functional elastic fibers, notably during ageing ofthe skin tissues, whether they be natural or induced by solar radiation.

The isoforms LOXL2, LOXL3 and LOXL4 are not or are little expressed inthe dermis and are not involved in elastogenesis (vide Example 4). TheLOX isoform is present in the dermis and can be associated with themicrofibrils, but LOX is involved in the formation of the functionalcollagen fibers and is not missing in adult skins. The absence of LOX istherefore not correlated with the loss of elasticity of the elasticfibers during ageing (vide Example 3).

This demonstration of the role of LOXL in elastogenesis was crucial forthe implementation of the present invention (vide Example 5).

The association between LOXL and the elastic fibers or the microfibrilswas clearly demonstrated by electron microscopy during theimplementation of the present invention. LOXL associated with themitrofibrils constitutes the framework on which the elastin isdeposited.

LOXL is the enzyme which is responsible for the maturation of theelastin by cross-linking and thus enables the formation of functionalelastic fibers.

Within the context of the present invention, the inventors haveimplemented a method of locating the expression of LOXL.

Notably, this method of location comprises the immuno-detection of LOXL.It is also possible by this method to demonstrate the expression of theprotein elastin. It has been demonstrated by the inventors' studies thatLOXL is detected in association with the dense deposits or on themicrofibrils, but not with the collagen fibers. Elastin was detected inthe same dense deposits and in the microfibrils. This detection is madeon reconstructed skin models, and notably on reconstructed skin models30 days after the application of the keratinocytes (vide Example 5).

The association of LOXL with the microfibrils and with the elasticfibers was also confirmed on the skin of the foreskin, notably bytransmission electron microscopy after immuno-detection.

LOXL is expressed in the dermis of the skin of the foreskin taken fromyoung, patients (a few months), which have still a large synthesis ofelastin. LOXL is not however expressed in the dermis of the skin, of theof the breast, of the abdomen or of the face of adult persons. Thisabsence of detection of LOXL in the dermis of the skin of the neck, ofthe breast, of the abdomen, or of the face, is confirmed in the adultwhatever the age. A high expression was also observed of LOXL in theepidermis of human skin, with however a late extinction of theexpression of this enzyme when the human skins originate from subjectsaged about 80 years old and more (vide Example 6).

With regard to scars, LOXL was not observed in the dermis of thesezones, neither three months after the scar, nor five years after theformation of the scar.

In this context, it is to be noted that the elastin which was present atthree months is no longer present on this scar tissue zone five yearsafter the formation of the scar.

The inventors have thus demonstrated the role of LOXL in the formationof elastic fibers, notably by using reconstructed skin models or dermisof the foreskin of young patients.

The inventors have also demonstrated the deficit of expression of LOXLin the scar tissue zones, as well as in the dermis of human skin ofvarying age, thus during ageing.

Amongst the isoforms of the lysyl oxidases, LOXL is one of the isoformswhich enables the cross-linking of the elastic fibers. However, onlythis isoform, LOXL, is missing in the adult for the cross-linking of theelastic fibers enabling functional fibers to be obtained.

The inventors have, from these unexpected discoveries, carried out ascreening method of an active principle which stimulates the formationof functional elastic fibers with the view to identifying activeprinciples for making cosmetic or pharmaceutical compositions.

The present invention further relates to the activation of the promoterof the human gene encoding LOXL (vide Example 7).

Various zones of activities of this promoter have been demonstrated. Thesequence of this promoter is given in the annex and is designated in thefollowing text by PrhLOXL.

On this promoter, the region corresponds to the nucleotides −712/−391(according to the numbering defined from +1 of translation of the hLOXLgene) which possesses an up-regulating activity on the reporter geneluciferase, which is expressed for example after transitionaltransfection in fibroblasts of the skin of the human foreskin.

The inventors have been able to define putative sites of regulation bynuclear factors. These factors have been correlated to cytokines orother factors known to act upon the transcription of certain genes.

Various regions of PrhLOXL have been able to be identified as beingactivating or inhibiting zones.

Notably, the regions −2172/−2002; −1438/−968; −712/−391; have beenlocated as being activating regions; and the regions: −2002/−1438;−968/−712 have been identified as being inhibiting regions. The −80/−1region is, not active and is situated down from +1 of transcription. Inthis numbering, the putative transcription +1 is situated in position−342 with respect to the site of initiation of the translation. In thisway, several sites of these regions have been shown which aresusceptible to regulating the hLOXL gene. These sites are notably twoputative sites of response to retinoic acid, two putative sites ofresponse to TGF-β (Transforming Growth Factor β), a putative site ofresponse to EGF (Epidermal Growth Factor), three putative sites ofresponse to oestrogens and two putative sites of response toglucocorticoids (GRE).

This implies that the active principles which stimulate theneo-synthesis and/or the activity of hLOXL and thus which stimulate theformation of elastic fibers which act upon the promoter of the hLOXLgene, and notably in these zones, either directly or indirectly, inmodulating the expression of a protein fixing onto these sites. It willtherefore be possible for a substance to be considered as active when itwill comprise a region which is capable either of associating with atleast one part of the sequence of nucleotides of PrhLOXL, and inparticular of associating with the putative sites defined above, or ofmodulating the expression of a protein which is capable of doing it.

The whole of the inventors' studies has enabled developing a method ofidentifying an active principle which stimulates the formation ofelastic fibers.

Within the context of the present invention, the inventors haveimplemented an in situ hybridization which thus enables locating andverifying the presence of the expression of the messenger RNAs whichencode LOXL in particular. This in situ hybridization is notably carriedout by double strand DNA probes which are labeled with digoxigenin onsections of reconstructed skin models obtained 30 days after theaddition of keratinocytes, and included in paraffin. This in situhybridization was also carried out in order to verify the expression ofthe messenger RNAs of tropoelastin and of collagen α1(I) (vide Example8).

The expression of the LOXL mRNAs is positive in the deep dermis andthroughout the whole epidermis. The expression of the tropoelastin mRNAis located near to the dermal fibroblasts and in the epidermis. Theexpression of the collagen Iα1 mRNA is located in the dermis but not inthe epidermis. This enables, within the context of the presentinvention, locating and verifying the presence of the expression of theLOXL mRNAs, notably in a reconstructed skin model, for example afterapplication of an active principle which stimulates the formation offunctional elastic fibers.

Within the context of the present invention, the hLOXL gene wasactivated by the addition of keratinocytes in a reconstructed skinmodel, and notably in the reconstructed skin model Mimeskin®, (Coletica,Lyons, France). The induction of the synthesis of the LOXL mRNAs isconcomitant notably with that of tropoelastin, and notably appears about6 days after the addition of the keratinocytes on the dermis equivalent.

The present invention has also enabled demonstrating the decrease in thelevel of expression of notably the hLOXL gene, as well as of the humanelastin gene, in fibroblasts originating from aged donors.

For this, the inventors used 5 strains of fibroblasts from the foreskin(FF) (originating from young infants) and 6 strains of adult fibroblasts(AF, of which 3 subjects of 20 years old on average, and 3 subjects of60 years old on average) originating from plastic surgery on theabdomen. The expression of the gene encoding the protein LOX was alsotested (vide Example 9).

The expression of these 3 genes of interest, as well as the one ofactin, was analyzed by real time RT-PCR. The invention is not limited tothis type of analysis. This technique enables precisely quantifying theexpression of a gene in comparing it to that of actin which isconsidered to be constant. The regulation of the level of expression ofthis gene can therefore be quantified.

The results presented in FIG. 12 first of all show that the synthesis ofLOXL mRNA drops spectacularly and statistically significantly in thefibroblasts of adults, with a drop of near to 70% with respect to thefibroblasts of the foreskin, whereas the elastin mRNA does not varysignificantly with age. This piece of data is in agreement with theliterature on elastin, since if the elastic tissue deteriorates and isnot replaced, it does not seem to be due to an inhibition of theactivity of the elastin gene.

The synthesis of LOX mRNA decreases on average by 40% in the AFs withrespect to the FFs, but since this enzyme is not always expressed innormal human skin, this variation is not very indicative of thephenomena in vivo.

It is advantageous to also stimulate the expression of elastin so as tostimulate the formation of elastic fibers even more.

The present invention provides a method enabling identifying theexpression of LOXL, notably in fibroblasts.

The present invention has aimed to implement these various techniques ina way as to identify active principles stimulating the formation ofelastic fibers.

In general, the methods of the present invention implement seeking theexpression of the protein LOXL, and notably seeking the expression ofthe messenger RNAs encoding LOXL (vide Example 10).

The invention also relates to the active principles which stimulate theformation of elastic fibers (vide Examples 11 and 12).

The invention also relates to the use of the enzyme LOXL, or of aderivative form, or of the active principles as described above, formaking cosmetic or pharmaceutical compositions (vide Examples 13 to 18).The stimulation of LOXL can be carried out at gene level, of themessenger RNA, or of the protein directly. This activation enables theformation of elastic fibers, notably by virtue of the cross-linking ofthe elastin by the enzyme LOXL.

Other aims, features and advantages of the invention will appear clearlyto the person skilled in the art upon reading the explanatorydescription which makes reference to the following Examples.

The Examples make up an integral part of the present invention and anyfeature appearing novel with respect to any prior state of the art fromthe description taken in its entirety, including the Examples, makes upan integral part of the invention in its function and in its generality.

Thus, every Example is of general scope.

Furthermore, in the Examples, all the percentages are given by weight,unless indicated otherwise, the temperature is expressed in degreesCelsius unless indicated otherwise, and the pressure is atmosphericpressure, unless indicated otherwise.

EXAMPLES Example 1

The invention has first of all covered the development of novel specificantibodies of LOX and LOXL but which are capable of detecting theirmature forms. The antibodies were developed against the mature regionsof LOX and LOXL. The antigenic regions were selected in order to presentthe minimum of similarity with the corresponding regions on the otherisoforms of the lysyl oxidases (LOS). The antibodies obtained againstthe regions of the peptides LOX^(V228-S280) were called anti-LOXmat andsimilarly for the antibodies obtained against the region of the peptidesLOXL^(R231-G368) called anti-LOXLpro.

In FIG. 1: description of the sequences of the LO defined for giving thespecific antibodies: This figure represents the steps which have led tothe selection of the antigenic regions in order to develop the anti-LOXand anti-LOXL antibodies.

FIG. 1(A): Schematic representation of hLOX (human LOX protein) andhLOXL (human LOXL protein).

The sequences of hLOX and hLOXL are indicated with open boxes, dotted inthe C-terminal regions, in order to highlight the regions of highsimilarity. The position of the cleavage of the pre-region and of thesite of cleavage by procollagen-C-proteinase (PCP), on the A22 and D169residues of hLOX respectively, was indicated. The position of thecleavage of the pre-region of LOXL, before the Q26 residue, of theN-terminal maturation site of the 56 kDa precursor (before Q135), andthe position of the cleavage sites by PCP of the LOXL precursor of 56kDa (before the D 338 residues), are indicated. The corresponding LOXLproteins Q²⁶-S⁵⁷⁴, D¹³⁵-S⁵⁷⁴, and D³³⁸-S⁵⁷⁴ would display a deducedmolecular mass of approximately 63 kDa, 54.6 kDa, and 26.7 kDa,respectively. The location of the recombinant peptides used forobtaining the anti-LOX antibodies were indicated: the G128-L212 peptidefor the anti-LOXpro, the V228-S280 peptide for the anti-LOXmat, and theD305-N373 peptide for the anti-LOXcat. The location of the recombinantpeptides used for developing the anti-LOXL antibodies were indicated:the R231-G368 peptide for the anti-LOXLpro and S355-D415 for theanti-LOXLmat.

FIG. 1(B): The percentage of similarity between the antigenic regions ofLOX and LOXL with their equivalents on the LO isoforms was indicated inthis Table.

In the Table of FIG. 1(B), hLOXL represents the human LOXL protein,bLOXL represents the bovine LOXL protein, mLOXL represents the mouseLOXL protein, hLOXL represent the human LOX protein, bLOX represents thebovine LOX protein; hLOXL2 represents the human LOXL2 protein, hLOXL3represents the human LOXL3 protein, hLOXL4 represents the human LOXL4protein.

The length column (aa) contains the value of the number of amino acidscontained in the corresponding regions.

In order to obtain the antibodies, the chimeric genes were constructedby inserting the defined sequence of hLOXL or hLOX in phase with thegene of glutathion-S-transferase (GST), in the BamHI-XhoI sites of theexpression plasmid pGEX-4T-3 (Amersham Biosciences).

The fusion gene GST-LOXL^(S355-D415) was constructed by introducing thecDNA sequence of HLOXL (cDNA hLOXL), produced by PCR with the senseprimer 5′-TTGGATCCAGCGTAGGCAGCGTGTAC-3′ (SEQ ID No 17), and antisenseprimer 5′-AAACTCGAGCATCGTAGTCGGTGGC-3′ (SEQ ID No 18).

The fusion gene GST-LOX^(G128-L212) was constructed by introducing hLOXcDNA amplified with sense primer 5′-TCGGATCCGGCTACTCGACATCTAGAGCC-3′(SEQ ID No 18) and antisense primer 5′-GTCCTCGAGACCGTACTGGAAGTAGCC-3′(SEQ ID No 19), respectively.

The fusion gene GST-LOX^(V228-S279) was constructed by introducing thehLOX sequence amplified with sense primer5′-TTGGATCCGTGCAGAAGATGTCCATGTAC-3′ (SEQ ID No 20) and antisense primer5′-TTTCTCGAGGCTGGGTAAGAAATCTGATG-3′ (SEQ ID No 21), respectively.

The fusion gene GST-LOX^(D306-N373) was constructed by introducing hLOXcDNA amplified with sense primer 5′-CACTATGGATCCTTGATGCCAACACCC-3′ (SEQID No 22) and antisense primer 5′-CACGACCTTTAGGATATCGTTTCCAGG-3′ (SEQ IDNo 23), respectively.

For the whole of these amplifications by PCR, the Taq polymerase HighFidelity (Roche Diagnostic, Meyman, France) was used.

The fusion proteins GST-LOX and GST-LOXL, as well as the rabbitpolyclonal antibodies were obtained and purified as described above forthe fusion proteins originating from the expression of the fusion genesGST-LOXL^(S355-D415) and GST LOX^(G128-L212) (Decitre et al., LabInvest, 78: 143-151, 1998; Borel et al., J. Biol. Chem., 276: 48944-49,2001).

For the adsorption experiments, the antibodies were incubated for 3hours at 20° C. with the fusion proteins, themselves adsorbed on anitrocellulose membrane, Hybond-ECL membrane (Amersham Biosciences)before the immuno-detection.

These pieces of work have first of all enabled demonstrating the matureforms of LOX and LOXL, by virtue of the immunochemical and biochemicalcharacterization of the mature proteins (vide Example 2, FIG. 2). Theantibodies developed are distinguished from those used in the prior artfor LOXL, which no not enable a recognition of the mature form of LOXL(Decitre et al., Lab Invest 78: 143-151, 1998; Borel et al., J. Biol.Chem., 276: 48944-49, 2001). The invention has been to use theanti-LOXLmat antibody and anti-LOXmat antibody, and this enableddemonstrating a protein of 31 kDa, which is recognized by theanti-LOXLmat but not by the anti-LOXmat, and which corresponds to themature form of LOXL. This part of the invention demonstrates a realprogress over the prior art, notably with reference to the patent ofCsiszar et al., which describes all the proteins originating from thegenes of the LO family without defining the features of them (WO01/83702 A2 patent application: Novel members of the lysyl oxidasefamily of amine oxidases related applications).

Example 2 Immuno-Detection of LOX and LOXL of Muscle Cells by Virtue ofthe Novel Antibodies Anti LOX and Anti-LOXL

On FIG. 2:

FIG. 2 represents photographs of electrophoreses which were carried outas indicated below. These electrophoreses demonstrate thecharacterization of the mature proteins of LOX and LOXL, of smoothmuscle cells (SMC) by virtue of the antibodies anti-LOX and anti-LOXL,identified in Example 1.

The proteins of the cell strain (L) and of the cell culture medium (M)of a cell line of rat smooth muscle (developed by Jean-Marie DanielLamaziere, Bordeaux) were extracted and detected by western blotting byusing the antibodies anti-LOXLmat, anti-LOXmat, anti-LOXLpro andanti-LOXpro. The cells were cultivated at 37° C. in an atmosphere of 5%CO₂ in DMEM medium (Sigma) containing 10% foetal calf serum, 2 mMglutamine and 50 μg/ml gentamycin.

The cell strain proteins, which are washed twice with PBS buffer, wereextracted for 2 hours at 4° C. with slow agitation in the lysis buffer(16 mM phosphate buffer pH 8, 0.5% NP40, protease inhibitors (CompleteMini, Roche Diagnostics), and urea 6 M). The lysates were diluted withtwo volumes of 16 mM phosphate buffer pH 8, with protease inhibitors(Complete Mini, Roche Diagnostics, Meylan, France), and centrifuged for5 minutes at 15,000 g. The soluble proteins were precipitated by adding10% trichloroacetic acid (TCA) before the electrophoresis.

The proteins of the culture media of cells cultivated for 48 hourswithout serum, are recovered, precipitated by adding 10% TCA or 50%saturated ammonium sulphate.

For the immuno-detection, the proteins are separated by 10%SDS-polyacrylamide gel electrophoresis. The proteins were transferredonto a polyvinylidene fluoride (PVDF) membrane (Immobilon P^(SQ),Millipore) and were immuno-detected as described above (Borel et al.,2001).

The developed antibodies thus enable characterizing and locating themature and immature forms of LOX and LOXL in the biological tissues.

Example 3 Demonstration of the Role of LOX and LOXL in Elastogenesis

The inventors have demonstrated that the LOX and LOXL proteins can beassociated with the formation of connective tissue in the dermis ofreconstructed skin models by immuno-histochemistry (FIG. 3). Thisdemonstration was obtained without any ambiguity by virtue of the use ofanti-LOX and anti-LOXL antibody couples, directed against thepro-enzymatic regions and mature regions of the two enzymes (LOX andLOXL).

On FIG. 3 representation is made of the immuno-histological detection ofLOXL and LOX in the reconstructed skin (RS) and normal human skin.

The immuno-detection of LOXL (A, C, E, G) on the reconstructed skin atdays 16 (A), 35 (C), and 45 (E), by using anti-LOXL^(R231-G368) (A, C,E) or anti-LOXL^(R231-G368) adsorbed with the corresponding peptideGST-LOXL^(R231-G368) before the immuno-detection (G). Theimmuno-detection of LOX (B, D, F, H) at days 16 (B), 35 (D), and 45 (F),by using anti-LOX^(V228-S279) (B, D, F) or anti-LOX^(V228-S279) adsorbedwith the corresponding peptide GST-LOX^(V228-S279) before theimmuno-detection (H). The immuno-detection of LOXL (I) and of LOX (J) inthe skin of human foreskin is carried out by using anti-LOXL^(R231-G368)(I) and anti-LOX^(V228-S279) (J). The position of the dermal-epidermaljunction is indicated with an open arrow, that of the dermal substratewith an arrow, and the location of the keratinocytes at day 16 isindicated with an arrow head.

The reconstructed skin (Mimeskin®, Coletica, Lyons, France) was preparedin Bouin's Native (LOX, LOXL, elastin) or in a 10% formol solution (forthe elastin), and then included in paraffin. 6 μm thick sections wereridded of paraffin and were whitened in glycine-HCl (100 mmol/l). Theanti-LOX and anti-LOXL antibodies are described above.

The antibodies were used at the following dilution: 1:500(anti-LOXL^(R231-G368)), 1:100 (anti-LOX^(V228-S279),anti-LOXL^(S355-D416)). The immune complexes were detected with a rabbit(goat) anti IgG conjugated with peroxidase (DAKO, Trappes, France), byusing diaminobenzidine as substrate (DAKO).

LOXL is thus an excellent candidate for participating in elastogenesisin a reconstructed skin model notably such as Mimeskin®.

Example 4 Demonstration of the Role of LOXL2, LOXL3, and LOXL4 inElastogenesis

The invention also covers the development of two novel anti-LOXL2antibodies, one of these antibodies theoretically also recognizing LOXL3and LOXL4. This has enabled defining whether these enzymes are expressedwith elastin in the dermis of a reconstructed skin model. The analysisby immuno-histochemistry by using the two anti-LOXL2 antibodies does infact show that this antigen, as well as the two antigenically linkedproteins LOXL3 and LOXL4, are not or are little expressed in the dermis,and that therefore, they do not participate in the elastogenesis.

On FIG. 4: the immuno-detection is represented on the sections ofreconstructed skin (16, 35 and 45 days) and of human foreskin skin withthe antibody anti LOXL2⁵¹⁷⁻⁵⁸¹ (left column) and the antibodyanti-LOXL2⁶⁶⁴⁻⁷²⁰ theoretically recognizing LOXL2, LOXL3, and LOXL4(right column).

The anti-LOXL2 antibodies were obtained against fusion peptidesGST-LOXL2, as described above (Decitre et al, Lab. Invest., 78, 143-151,1998). The fusion gene GST-LOXL2⁵¹⁷⁻⁵⁸¹ was constructed by introducingthe sequence 1543 to 1747 of the human LOXL2 gene (hLOXL2) in theplasmid, as described above.

This segment was generated by PCR with the sense primer5-GAGCTGGGATCCGCGCACTGCC-3′ and antisense primer5′-GGCTGAGTCGACGAGGCAGTTCTCC-3′.

The fusion gene GST-LOXL2⁶⁶⁴⁻⁷²⁰ was constructed by introducing thecorresponding hLOXL2 sequence, by virtue of the sense primer5′-CACAGGATCCGAAGGAGACATCCAGAAG-3′ and antisense primer5′-TTTCTGAGCTCCTGCATTTCATGATG-3′.

The fusion proteins and the anti-rabbit antibodies generated againstthese proteins were prepared as described above. The antibody againstthe 517-580 peptide was called anti-LOXL2, since this region is specificof LOXL2.

The antibody against the 664-734 peptide was called anti-LOXL-R (for<<relative to>>), since this region of LOXL2 possesses a high similaritywith LOXL3 and LOXL4 (about 74.6% and 60.5%, respectively).

The reconstructed skins (Mimeskin®, Coletica, Lyons, France) at 16 days(RS-D16), 35 days (RS-D35) and 45 days (RS-D45), and the skin of thehuman foreskin are analyzed as above by immuno-histochemistry with theanti-LOXL2-R and anti-LOXL2 antibodies. Anti-LOXL2 shows an expressionof LOXL2 in the epidermis and not in the dermis, while the antibodydirected against the common C-terminal region of LOXL2, LOXL3, and LOXL4confirms the expression of these enzymes in the epidermis and shows alow expression in the dermis but in an zone which does not correspond tothe sites of elastogenesis.

LOXL2, LOXL3 and LOXL4 are therefore not involved in elastogenesis.

Example 5 Demonstration of the Role of LOXL in Elastogenesis

The association between LOXL and LOX on the one hand, and the elasticfibers or the microfibrils on the other, was clearly demonstrated intransmission electron microscopy by the present invention.

LOX and LOXL associated with the microfibrils constitute the frameworkon which the elastin is deposited, whereas only LOX is associated withthe formation of the collagen fibers (vide FIG. 5).

On FIG. 5: The immuno-detection of LOXL, of LOX and of elastin isrepresented by transmission electron microscopy in the dermal part ofthe reconstructed skin 30 days after the application of thekeratinocytes, and of the normal human skin.

The tissues were fixed for 3 hours at 4° C. with 4% paraformaldehyde inPBS buffer containing 0.1% glutaraldehyde, and were then washed inphosphate buffer containing 0.4M of sucrose cacodylate and 0.2M lysine,dehydrated in solutions of ethanol, and included in LR White (Euromedex,France). The detection was carried out with primary antibodies dilutedto 1:50 in Tris-HCl buffer at pH 8.2, to which 1% bovine serum albumin(BSA) is added. The immune complexes are detected with an rabbitanti-IgG antibody conjugated with colloidal gold particles of 10 and 20nm (Biocell, Tebu, France) diluted to 1:40. The samples were contrastedwith 3% aqueous uranyl acetate and lead citrate, and were then examinedunder a JEOL 1200 EX transmission electron microscope. Theimmuno-detection was carried out on the reconstructed skin (A-D) and onthe skin of human foreskin (F-I).

On the reconstructed skin, it was carried out with the antibodies:anti-LOXL (A, B), anti-LOX (C), anti-elastin (Elm) (D), humananti-elastin antibodies being commercially available (Sigma, USA) anddiluted to 1:50, and a negative control without primary antibody in thedermis (control) (E). A double labelling (F-I) was made on the skin ofthe human foreskin.

References A-D: Immuno-detection of LOXL, LOX and elastin by electronmicroscope in the dermal part of the reconstructed skins at 45 days.

Reference E: Positive control with anti-elastin and anti-collagen Iantibodies in the dermis of reconstructed skins at 45 days, i.e. 30 daysafter the addition of keratinocytes.

References F and I: Double immuno-detection of LOXL, LOX, elastin andcollagen by electron microscopy in the dermal part of human foreskin.

References G-H: Double-labelling in the dermal part of the humanforeskin with the rabbit anti-LOXL antibody (the rabbit anti-IgG isconjugated with 10 nm gold particles) and the murine anti-elastinantibody (the mouse anti-IgG is conjugated with 20 nm gold particles).

Keys in the Figure: m: microfibrils, c: collagen fibers, e: amorphouselastin. Bar of the scale: 500 nm.

LOXL (A-B) is detected in association with the dense deposits or on themicrofibrils, but not with the collagen fibers which appear in white onthese sections. The labelling of LOX (C) is low, although a few goldparticles could be found with the dense deposits, the microfibrils andthe collagen. The anti-elastin antibodies detected the same densedeposits and the microfibrils (D). The association of LOXL and LOX tothe microfibrils and to the elastic fibers was confirmed in the skin ofthe human foreskin, by electron microscopy after immuno-detection (G-H).As in the observations on the reconstructed skin models, LOXL is notassociated with the collagen fibers, opposite to the LOX which is verypresent with the collagen fibers and little present on the microfibrils.The LOXL antigens were detected in association with the microfibrils andaround the elastic fibers of the skin of human foreskin. LOXL is notassociated with the amorphous elastin which extends around themicrofibrils, but is mainly observed on their periphery, and not withthe collagen fibers.

LOXL is associated with the elastic fibers in the reconstructed skinmodels and in the skin of the human foreskin.

Example 6 Demonstration of the Relationship Between the Expression ofLOXL and Elastogenesis

LOXL and LOX are expressed in the dermis of the skin of the foreskintaken from young patients (a few months) still having a high elastinsynthesis. LOXL is not however expressed in the dermis of adult skin, ofthe neck, the breast, the abdomen or the face, whereas LOX is alwaysexpressed in the dermis (FIG. 6).

On FIG. 6: the immuno-detection of LOX and LOXL in the human skin isrepresented.

The antibodies anti-LOX (A, C, E, G) and anti-LOXL (B, D, F, H) wereused for detecting the expression of LOX and LOXL in samples of skin ofthe foreskin (A, B), of the neck (C, D), of the breast (E, F) and of theabdomen (G, H) originating from the tissue bank of the Edouard HerriotHospital, Lyons, France. The tissues were fixed with Bouin's reagent,included in paraffin, and treated for the immuno-detection as wascarried out for the immuno-detections which are described above.

The absence of detection of LOXL in the dermis of the skin of the neck,of the breast, of the abdomen or of the face, is confirmed in the infantand the adult (FIG. 7: abdomen).

On FIG. 7: The immuno-detection of LOX and LOXL in skins of the humanabdomen taken at various ages is represented.

The antibodies anti-LOX (A, C, E, G) and anti-LOXL (B, D, F, H) wereused for detecting the expression of LOX and LOXL in samples of skin ofthe abdomen taken at 1.5 years old (A, B), 35 years old (C, D), 60 yearsold (E, F) and 91 years old (G, H) originating from the tissue bank ofthe Edouard Herriot Hospital. The tissues were fixed with Bouin'sreagent, included in paraffin, and treated for the immuno-detection suchas described for the preceding immuno-detections.

During the same pieces of work, a high expression was observed of LOXand LOXL in the epidermis of human skin, with a very late extinction ofthe expression of these 2 enzymes (91 years old) (FIG. 7).

In the scars, neither LOXL nor LOX were able to be observed in the scartissue zones 3 months after the scar and 5 years after the scar. It isto be noted that the elastin was immuno-detected at 3 months anddisappeared at 5 years in this scar (FIG. 8).

On FIG. 8: The immuno-detection of LOX and LOXL in scar tissue skins atvarying periods after the healing is represented.

The antibodies anti-LOX (A, D, G), anti-elastin (B, E, H) and anti-LOXL(C, F, I) were used for detecting the expression of LOX, of elastin andof LOXL in samples of skin of the neck of a patient of 17 years old,around the scar (<<normal>> zone, A-C), 3 months (D-F) or 5 years old(G-H) after a healing. The tissues were fixed with Bouin's reagent,included in paraffin, and treated for the immuno-detection such as wasdescribed for the preceding immuno-detections. The labeling of elastinrequires a demasking with the aid of 0.2% hyaluronidase (Sigma).

By virtue of these Examples, the invention demonstrates that thereexists: (i) an undeniable implication of LOXL in the formation ofelastic fibers in reconstructed skin models and in the dermis of theforeskins of young patients, and (ii) a veritable deficit of expressionof LOXL in the dermis of the human skin at varying ages and in thescars. LOXL is therefore indeed the only lysyl oxidase isoform which iscapable on the one hand of enabling the cross-linking of the functionalelastic fibers and, on the other, of being missing in the situationwherein a cross-linking of the elastic fibers is necessary in order toproduce functional fibers. LOX, which could also be associated with theformation of elastic fibers, is not missing in the skins of the adult.

Example 7 Study of the Pre-Transcriptional Regulation of the LOXL Gene

The invention has enabled demonstrating further that the human LOXL gene(hLOXL) can be activated at its promoter level (FIG. 9). The Sequence IDNo. 3 describes the nucleotides going from −2730 to −1 of the sequenceof this promoter. Several zones of activity of the hLOXL promoter weredemonstrated. Notably, the region corresponding to the nucleotides−712/−391 (according to the numbering defined from +1 of translation ofthe LOXL gene) possesses an up-regulating activity on the reporter geneluciferase, expressed after transitional transfection in fibroblasts ofskin of the human foreskin (FIG. 9).

It is therefore a pre-transcriptional up-regulation of the hLOXL gene,which indicates that it is possible to activate the synthesis of thisgene, and therefore of the corresponding hLOXL protein, since theinventors had demonstrated beforehand that the variations of theexpression of hLOXL can be traced concomitantly at the level of thegenes and/or the proteins. This had also been demonstrated for LOX(Decitre et al., Lab. Invest., 78, 143-151, 1998).

A study of the nuclear sequence PrLOXL with the aid of the softwareTransfac® on the Internet has enabled us to define putative sites ofregulation by nuclear factors. These factors were correlated withcytokines or other effectors known for acting on the transcription ofcertain genes via these transcription factors. The most interestingsites are presented in FIG. 10. This scheme recapitulates this analysisand indicates 2 putative sites of response to retinoic acid, 2 to TGF-β,1 to EGF, 3 to oestrogens and 2 to glucocorticoids. We have thus beenable to define several sites which could regulate the transcription ofthe LOXL gene, since they were studied in the regulating zones. Theseare the putative elements of response to retinoic acid, to TGF-β, to EGFand to glucocorticoids. The zones which correspond to these putativesites of regulation by retinoic acid and oestrogens seem to have a realactivating effect on the transcription, since the activity of thepromoter drops by about 50% and 60% respectively without these elements.The site of regulation by the TGF-β seems to lower the promotingactivity.

The tools thus described can be used for the screening of activeprinciples having an agonist or antagonist action upon the promoter ofhLOXL, and more particularly upon the putative sites of recognition.

It is so that is advantageous to seek active principles comprising aregion which hybridizes with at least one part of the sequence ofnucleotides of the promoter of hLOXL, or which induces effector proteinshaving this property.

Functional Analysis of the Promotor of the hLOXL Gene

The promoter of the human LOXL gene (PrhLOXL) was defined by virtue ofthe sequences from the data bases. Since the site of initiation of thetranscription was unknown, the inventors numbered it with respect to the+1 of translation. However, the EST (Expressed Sequence Tags) cDNAsearch, which corresponds to this region, did not give any sequencefurther up from position −342, which enables supposing that theinitiation of the transcription of the hLOXL gene is done in this region(without TATA box). Specific primers were shown on this sequence inposition −2172 and +189 (exon 1). They enabled the amplification and theisolation of the PrhLOXL from human genomic DNA originating from skinfibroblasts. It was cloned and sequenced, its sequence proving to beconform to that predicted. Then, the promoter, known as <<entire>>,going from −2172 to −1, was able to be sub-cloned in the pGL3-basicvector (Promega, Charbonnières, France) for the study of it ineukaryotic cells. It was placed up from the reporter gene, theluciferase gene. Thus, the production of luciferase by the transfectedcells is under the control of the PrhLOXL and therefore proportional toits activity. The cells are transfected at the same time with thepromoter, intensely and reproducibly expressing β-galactosidase (β-Gal),enabling the results to be normalized. For a same condition, theluciferase and β-Gal enzyme activities are measured.

The PrhLOXL was progressively reduced (deletion 5′) so as to determinethe role of the regions taken out. The aim was to study the regulationof the PrhLOXL in the fibroblasts of human skin, the transfection ofthese cells was developed. In contrast to the cell lines which transfecteasily, normal fibroblasts transfect very poorly. Superfect® (Qiagen,Courtaboeuf, France) was selected, since it enables the transfection ofabout 40% of fibroblasts in culture.

The constructions made, as well as their activity in the foreskinfibroblasts, are presented in FIG. 9. The inventors located three largeactivating regions of the transcription and two inhibiting regions. Forexample, the region −712→−391 is very activating since the activity ofthe promoter drops considerably when it is taken out (construction−391→−1). This study has enabled specifying the zones to be studied forstimulating the transcription of the PrhLOXL.

Notably, FIG. 9 represents the luciferase/β-galactosidase activity as afunction of the sequence of the promoter PrhLOXL. This Figure enablesfacilitating the understanding of the definition of the activating andinhibiting regions of the promoter within a human fibroblast cell of theskin of the foreskin.

The successive reductions of the PrhLOXL in 5′ have enabled generating 7constructions, bearing shorter and shorter sequences of the promoter upfrom the reporter gene luciferase pLL-2172, pLL-2002, pLL-1438, pLL-712,−pLL-391, −pLL-81. The constructions were transfected in fibroblasts ofthe foreskin of human skin, and the luciferase activity was measured. Inparallel, the cells are also transfected with a plasmid bearing theβ-galactosidase gene, under the control of the promoter SV40, so as toserve as a transfection effectiveness control. The final valuescorrespond to the luciferase activity (indicating the activity of thesequences of the hLOXL promoter) compared to the β-galactosidaseactivity (showing the effectiveness of transfection). The evolution ofthe activities enable defining several regulation zones on the promoter,including 3 activating zones, shown by the signs +(−2172→−2002;−1438→−968; −712→−391) and 2 inhibiting zones, shown by the signs−(−2002→−1438; −968→−712). The −81→−1 promoter is not active and issituated down from the +1 of transcription. The putative +1 oftranscription is situated in position −342 with respect to the site ofinitiation of the translation.

FIG. 10 represents a schematic view of the promoter of the hLOXL gene,and notably identifies the putative sites of regulation of thetranscription of the hLOXL gene. The zones indicated by a “+” signcorrespond to a zone of activation of the expression of the gene, thoserepresented by a “−” correspond to a zone of inhibition of thisexpression.

Example 8 Demonstration of the Activation of LOXL by the Introduction ofKeratinocytes in a Reconstructed Skin Model

The detection of the expression of the gene encoding LOXL isdemonstrated by the in situ hybridization of the messenger RNA of LOXLwith double strand DNA probes which are labeled with digoxigenin, onsections included in paraffin.

In FIG. 11, which represents skin model sections (Mimeskin®) at day 35:

(A) the expression of LOXL is positive in the deep dermis and throughoutall the epidermis.(B) The expression of LOX is positive in all the dermis and in thesuprabasal layers of the epidermis.(C) The expression of tropoelastin (TE) is found in association with thedermal fibroblasts and in the epidermis.(D) The expression of the gene COL1A1 (collagen α1 (I)) is detected inthe dermis but not in the epidermis.(E) Control without probe.

The position of the DEJ is indicated by an open arrow, the position ofthe porous dermal substrate is indicated with arrows, and the positivecells are indicated with arrow heads.

The double strand DNA probes are produced by PCR. The following primerswere used, respectively:

For the gene of the Ialpha1 collagen, sense 5′-GTGGAGAGTACTGGATTG-3′(SEQ ID No 14) and antisense 5′-TCGTGCAGCCATCGACAG-3′ (SEQ ID No 15),for tropoelastin, sense 5′-GTATATACCCAGGTGGCGTG-3′ (SEQ ID No 10) andantisense 5′-CGAACTTTGCTGCTGCTTTAG-3′ (SEQ ID No 11); for hLOX, sense5′-GGTGGCCGACCCCTACTACATCC-3′ (SEQ ID No 12) and antisense5′-GCAAATCGCCTCTGGTAGCCATAGTC-3′ (SEQ ID No 13); for hLOXL, sense5′-GACATAACCGACGTGCAGCC-3′ (SEQ ID No 8) and antisense5′-ATCCACGTTCGCTCCCTGAG-3′ (SEQ ID No 9).

The DNAs are amplified with Taq Polymerase (Promega, Charbonnières,France) and Dig-11-dUTP (Roche Diagnostic, Meylan, France) as labellernucleotide, and they are then purified after electrophoresis on agarosegel by using the QIAquick extraction kit (Qiagen, Courtaboeuf, France).The in situ hybridization was carried out on sections included inparaffin. The samples are ridded of paraffin and treated with proteinaseK (Roche) at 2 μg/ml for 15 minutes at 20° C. The endogenous peroxidasesare inhibited as indicated in the TSA⁺ amplification kit (NEN, Boston,USA). A pre-hybridization is carried out for 2 hours at 37° C. in 20 mMphosphate buffer at pH 7.4, with 50% deionised formamide, 2×SSC (sodiumsalt citrate), 5 mM EDTA, 2.5×Denhardt's solution, 200 μg/ml denaturedherring DNA, 1 mg/ml salmon sperm DNA, and 10 mg/ml tRNA. Thehybridization is carried out for 16 hours at 37° C. in 20 mM phosphatebuffer, with 50% deionised formamide, 2×SSC, 5 mM EDTA, 2.5×Denhardt'ssolution, 200 μg/ml denatured herring sperm DNA, and 10% dextransulphate, with or without the prior-denatured probe for 5 minutes in aboiling water bath. After the hybridization, the sections are washed at20° C. (or 37° C. for the collagen) in 2×SSC/50% formamide, 1×SSC/50%formamide, 1×SSC, and 0.5×SSC. After dehydration, the hybrids labelledwith the digoxigenin are detected with an anti-DIG antibody conjugatedwith horseradish peroxidase (Roche). The final detection of thecomplexes is carried out by using the TSA⁺ amplification kit (NEN). Thepositive signals correspond to the activity of the alkaline phosphataselinked to the amplification procedure of the TSA kit, after 2 hours ofactivity at ambient temperature, and defined by the precipitation of thetetrazolium salts formed (by using the Nitro BlueTetrazolium/bromochlorylindolophosphate (NBT/BCIP) substrates).

The invention demonstrates that the LOXL and LOX genes can be activatedby the addition of keratinocytes in a reconstructed skin model(Mimeskin®, Coletica, Lyons, France), as the tracking of the expressionof the mRNAs by in situ hybridization demonstrates (FIG. 11).

The induction of the synthesis of LOXL is concomitant with that oftropoelastin (6 days after the addition of keratinocytes on theequivalent dermis).

The LOX gene is also activated after the addition of the keratinocytes,at the same time as the collagen Iα1 gene (Col1A1).

Example 9 Demonstration of a Drop in the Level of the Expression of theLOX Gene in Adult Fibroblasts

The inventors used five strains of fibroblasts from the foreskin (FF)(originating from young infants) and 6 strains of adult fibroblasts (AF,3 of 20 years old on average, and 3 of 60 years old on average)originating from plastic surgery on the abdomen. The expression of thethree genes of interest, as well as of actin, was analyzed by real timeRT-PCR (quantitative reverse transcriptase polymerase chain reaction,FIG. 12). This technique enables precisely quantifying the expression ofa gene in comparing it to that of the actin (considered as constant).The regulation of the level of expression of this gene can therefore bequantified.

The results presented in FIG. 12 first of all show that the synthesis ofLOXL mRNA drops spectacularly and statistically significantly in thefibroblasts of adults, and this as from the age of 20 years, with a dropof near to 70% with respect to the fibroblasts of the foreskin, whereasthe elastin mRNA does not vary significantly with age. This piece ofdata is in accordance with the literature on elastin: if the elastictissue deteriorates and is not replaced, it does not seem to be due toan inhibition of the activity of the elastin gene.

The synthesis of LOX mRNA decreases on average by 40% in the AFs withrespect to the FFs, but with the individual variability, this deviationis not very significant.

The total RNAs are purified with the <<SV 96Total RNA Isolation System>>kit (Promega, Charbonnières, France). The purified RNAs are eluted in100 μl of RNase-free water (Promega, Charbonnières, France), determinedand distributed into plates (96-well, 10 μl total RNA at 5 ng/μl byPCR). The primers selected for the implementation of this work are thefollowing and are the subject of Table I:

TABLE I Position on Melting Size the human temperature Gene Name(nucleotides) Human sequence gene (MT) ELN 1 Ela 20 GTA TAT ACC CAGSense: +443 62° C. GTG GCG TG 2 Ela 21 CGA ACT TTG CTG Antisense: 62° C.CTG CTT TAG +799 LOX Ox 64 21 ACG TAC GTG CAG Sense: +676 60° C. AAG ATGTCC Ox 65 21 GGC TGG GTA AGA Antisense: 59° C. AAT CTG ATG +841 LOXL 30L1 19 GAC TTC GGC AAC Sense: +1480 60° C. CTC AAC C 30 L2 20 TGT TGC AGAAAC Antisense: 60° C. GTA GCG AC +1701 ACTIN Actin 20 GTG GGG CGC CCC Usense 72° C. AGG CAC CA Actin 24 CTC CTT AAT GTC D antisense 57° C. ACGCAC GAT TTC

The technique of real time RT-PCR is carried out with the <<Quanti TectSYBR Green RT-PCR>> kit (Qiagen, France) on wells containing mRNA, in anOPTICON thermocycler, which carries out amplification cycles. Theretrotranscription (RT) is performed for 30 minutes at 50° C., followedby 15 minutes at 95° C. in order to inhibit the reverse transcriptase,to activate the polymerase and to denature the complementary DNA (cDNA)obtained. 50 chain polymerization cycles (PCR) are carried out (15seconds at 94° C., 30 seconds at 60° C., 30 seconds at 72° C.). At everycycle end, the fluorescence, which is proportional to the number offragments amplified, is read. The level of expression is defined by theratio of expression of each gene with respect to actin.

As the preceding pieces of work demonstrate the implication of LOXL inelastogenesis and its disappearance in adults' skins, the followingpoint of the invention has borne upon the levels of expression of thegenes LOXL, of LOX and of elastin in fibroblasts of varying ages.

The Examples above demonstrate that the synthesis of the products of thegenes LOXL and LOX can be activated at gene level. The activation of thesynthesis of the mRNAs of LOXL and of tropoelastin is concomitant inreconstructed skin. The activation of the genes of LOXL and oftropoelastin enables the formation of the elastic fibers. A screening ofactive principles enables leading to the identification of moleculeswhich can simultaneously re-induce the expression of the genes ofelastin and of LOXL, so as to stimulate the elastogenesis.

In conclusion, the invention enables demonstrating the directrelationship of LOXL with the elastic fibers, the importance of LOXL forforming elastic fibers in reconstructed skin, and the absence of LOXLfrom tissues wherein the synthesis of functional elastic fibers does nottake place (adult tissues, scars). The invention relates notably to amethod of screening for detecting novel molecules which are capable ofconcomitantly inducing the synthesis of LOXL and of elastin with theview to re-inducing the expression of functional elastic fibers inreconstructed skin, skin biopsies, and human skin.

Example 10 Analysis of the Expression of the Messenger RNAs of LOXLand/or of Elastin, e.g. by Qualitative RT-PCR with or without thePlacing in Contact of Active Principles the Activity of which is to beTested

The active principles were tested at 1% (v/v) on fibroblasts of normalhuman skin (originating from the foreskin of the infant or originatingfrom the adult). The culture was carried out, e.g. in a monolayer on24-well culture plates, in a defined medium without serum (FibroblastBasal Medium). The cells were sown, e.g. at 40,000 per cm². At theconfluence, the cells are placed in contact with the activesadvantageously for 24 hours. In parallel, a non-treated control (mediumalone) and three positive controls (TGF-β at 1 ng/ml, IL-1α at 50 pg/mland Phytokine® (Coletica, Lyons, France) at 2% (v/v)) are advantageouslycarried out, e.g. on the same culture plate.

The TGF-β at 1 ng/ml and the IL-1α at 50 pg/ml were tested beforehandand the stimulation of the synthesis of elastin mRNA induced by thesetwo cytokines at these concentrations was verified by an analysis of themRNAs, e.g. by quantitative RT-PCR (x10 for TGF-β and x6 for IL-1alpha). After the time of placing the actives in contact with the cells,e.g. 24 hours, the media are removed and the cells are preserved e.g. bydry freezing at −80° C. after a rinsing in phosphate buffer pH 7.4. Thetotal RNAs are extracted e.g. with the aid of an extraction kit of 96wells on silica columns and were determined on a 96-wellspectrophotometer at 260 nm (purity indicator: protein determination at280 nm). The RNAs are diluted e.g. to 5 ng/μl. The qualitative RT-PCR in1 step is carried out e.g. on 50 ng of initial RNA on a 96-well plate,on the genes of actin, elastin, of LOX and of LOXL. The specific primersof each gene are used e.g. at 0.5 μM:

sense elastin gene: (SEQ ID N^(o) 24)1Ela 5′-GTA TAT ACC CAG GTG GCG TG-3′; antisense elastin gene:(SEQ ID N^(o) 25) 2Ela 5′-CGA ACT TTG CTG CTG CTT TAG-3′;Sense LOXL gene: (SEQ ID N^(o) 26) 30L1 5′-GAC TTC GGC AAC CTC AAG C-3′;Antisense LOXL gene:  (SEQ ID N^(o) 27)31L1 5′-TGT TGC AGA AAC GTA GCG AC-3′; sense LOX gen: (SEQ ID N^(o) 28)Ox64 5′-ACG TAC GTG CAG AAG ATG TCC-3′; antisense LOX gene:(SEQ ID N^(o) 29) Ox65 5′-GGC TGG GTA AGA AAT CTG ATG-3′;sense Actin gene: (SEQ ID N^(o) 30) Actin U 5′-GTGGGGCGCCCCAGGCACCA-3′;antisense Actine gene: (SEQ ID N^(o) 31)Actin D 5′-CTCCTTAATGTCACGCACGATTTC-3′.

The amplification parameters were advantageously the following: 48° C.,30 min; 94° C., 2 min; (94° C., 30 seconds; 60° C., 30 seconds; 68° C.,30 seconds) 28 cycles for actin, 30 cycles for LOXL, 32 cycles for LOX,or 34 cycles for elastin; 68° C., 10 min; 14° C., infinity. Afteramplification, the products are for example mixed at the rate of 3 μl ofactin amplification products +5 μl of elastin gene amplificationproducts +5 μl of LOX gene amplification products +5 μl of LOXL geneamplification products. A loading buffer is added (2 μl) and the totalvolume (20 μl) is deposited on a pre-poured agarose gel (Invitrogen,France) e.g. at 2%. The inventors visualized the levels of expression bymeans known to the person skilled in the art and e.g.: the bands of thesamples were visualized under UV in a black chamber after migration (15minutes) and were photographed digitally. The photographs of the gelswere analyzed by image analysis and quantification of the intensity ofthe bands (Phoretix1D, France). The level of expression of the genes ofelastin, of LOX and of LOXL were expressed in percentage variation withrespect to those obtained for the negative control (without treatment).

Interpretations of the Results:

<<young>> cells and <<mature>> cells:

It is noted that the cells of the foreskin express quantities of mRNAencoding elastin at a level which is identical to that observed onaverage in the adult, while they are very much greater than the case ofthe mRNA encoding LOXL, as well as in the case of the mRNA encoding LOX.It is therefore possible to reverse this decrease of the expression ofLOXL and eventually of LOX in the aged cells, and a screening of activeprinciples in this sense was performed.

Screening of Active Principles:

The amounts of cDNA of each test are compared to the amount of actincDNA and then to the negative controls (without actives). A preliminaryanalysis enabled considering the tests presenting an increase of elastin(Eln) mRNA of about 1.3 times, of about twice LOXL, to be significant.Of more than 900 molecules or active extracts tested, 13 actives meetthese criteria at the concentrations tested and under the definedconditions. These actives are the following and are, the subject ofTable II

TABLE II Eln LOXL LOX Control Control Control Name multiplied by:multiplied by: multiplied by: Dill (fruit) 2.28 2.03 3.08 currant 4.11 24.55 Cardamon 2.08 2 5.57 Black radish 2.88 2.13 2.92 Box holly 1.58 2.42.53 Cinnamon 1.56 2.09 5.08 Lactic ferments 2.37 2.04 9.69 Potato 2.41.88 3.55 Silk protein 2 3.05 3.25 Oats 2.37 2.04 9.69 Asa foetida gum1.35 2 3.19 ethyl hexenoate 1.5 2.33 3.09 methyl butyrate 1.43 3.24 5.08ethyl decadienoate 2.04 2.32 3.64

The plant extracts were obtained in allowing the plants to soak at 2-5%(w/w) in a water/(alcohol, glycol or polyol) mixture (such as ethanol,glycerol, butylene glycol and other glycols, xylitol etc. . . . ) 100/0to 0/100. The extracts obtained were then filtered or distilled so as torecover the soluble fraction which is then filtered in sterile manner.The chemical molecules originate from Sigma (Saint-Louis, USA) and areused diluted or dispersed at 1% in an alcohol or a glycol.

Conclusion: 13 actives from the bank of 960 actives are capable, underthe conditions considered, of significantly activating the level ofsynthesis of mRNA of the genes encoding LOXL, LOX and elastin, in thefibroblasts of the abdomen of the mature age adult (donor of 63 yearsold in this case).

Example 11 Study of Effectiveness of a Cosmetic or DermopharmaceuticalActive by e.g. Real Time RT-PCR

The actives selected after the first step of screening were tested atvarious concentrations of between 0.1% and 5%, (v/v) on fibroblasts ofnormal (adult) human skin. The culture was carried out e.g. in monolayerin 24-well plates, in a defined medium without serum. (Fibroblast BasalMedium). The cells are sown e.g. at 40,000 per cm². After the time ofplacing the actives in contact with the cells (24 hours), the media wereremoved and the cells were preserved e.g. by dry freezing at −80° C.after a rinsing with phosphate buffer at pH 7.4. At the end ofexperimentation, the content of mRNA of elastin, of LOXL and of actin isevaluated by an mRNA analysis technique, e.g. by real time RT-PCR. Forthis, the couples of primers enabling the amplification of specificfragments of these genes are those described above (Example 10).

After extraction e.g. with the aid of an extraction kit in 96-wells onsilica columns and determination on a 96-well spectrophotometer at 260nm, the RNAs are diluted e.g. to 5 ng/μl. The RT-PCR reactions (ReversePolymerase Transcription Chain Reactions) were carried out byquantitative real time RT-PCR with the aid of the “Opticon” system (MJResearch). Advantageously, the reaction mixture (50 μl) introduced intothe wells was the following, for each sample:

10 μl of RNA at a concentration of 5 ng/μl,

The specific primers of the various labels sought after,

Reaction mixture (Qiagen-25 μl 2xQuantiTect SYBR Green RT-PCR master mixcontaining 5 mM MgCl2+0.5 μl QuantiTect RT mix), the label SYBR Green Iinserting in the DNA double strands during the elongation step.

The RT-PCR conditions were advantageously the following:

Reverse Transcription: 30 minutes at 50° C., then 15 minutes at 95° C.,PCR reactions: [15 seconds at 94° C., 30 seconds at 60° C. and 30seconds at 72° C.], 50 cycles.

The absence of contamination and the purity of the amplified productswere verified e.g. via the fusion curves of the amplified PCR products.The products presenting a double peak or an abnormal fusion temperaturewere eliminated.

Analysis and Method of Calculation:

The incorporation of fluorescence in the amplified DNA was evaluatedcontinuously during the PCR cycles. This system enabled obtaining curvesof fluorescence measurement as a function of the number of PCR cyclesand thus enabled evaluating a relative amount of amplified DNA.

In order to take account of the cell population present, all the resultswere compared to the <<actin>> signal, which was used as housekeepinggene. According to the experimentation, the threshold of measurement ofthe C(T) (=Cycle Threshold) was fixed for T between 0.05 and 0.01, andthen an arbitrary measurement unit is calculated for each gene accordingto the formula:

Sgene<<x>>=10⁷×(½)^(C(T)gene<<x>>)

C(T)gene <<x>> signifying the number of cycles necessary to attain thecycle threshold of 0.01-0.05 of the gene <<x>>.

The values of the genes of interest were compared to the <<actin>>signal by calculation of the ratio:

R=Sgene<<x>>/Sactin.

These ratios were compared between the treated and non-treated samples,“x” being the LOXL gene, or the elastin gene.

Results: amongst the actives selected, the results obtained, as anexample for two of them, are presented in Table III

TABLE III LOXL LOX El Control Control Control Name multiplied by:multiplied by: multiplied by: methyl butyrate at 0.89 1.04 0.92 0.01%methyl butyrate at 1.56 1.76* 0.96 0.1% methyl butyrate at 1% 2.10*2.17* 1.25 methyl butyrate at 5% 0.91 0.91 1.70* Silk protein at 0.01%1.18 0.96 1.00 Silk protein at 0.1% 1.46* 0.96 1.12 Silk protein at 1%2.39* 1.16 1.24 Silk protein at 5% 2.05 1.37 1.37 *statisticallysignificant results p < 0.05 (One Way Anova test)

Conclusion: the actives selected enable activating the level ofsynthesis of mRNA of the genes encoding LOXL, LOX and elastin, in thefibroblasts of the abdomen of mature age adult (donor of 63 years old inthis case): The study made enables determining the optimalconcentrations of use for each active selected.

For Examples 1 to 11: the person skilled in the art will know how todraw the adequate teaching from these Examples in order to make variantsof the compositions (formulations) described.

Example 12 Use of the Products of the Invention in Cosmetic orPharmaceutical Formulations of Oil-in-Water Emulsion Type Formulation12a:

A water qsp 100 Butylene Glycol 2 Glycerol 3 Sodium Dihydroxycetyl 2Phosphate, Isopropyl Hydroxycetyl Ether B Glycol Stearate SE 14 Triisononaoin 5 Octyl Cocoate 6 C Butylene Glycol, 2 Methylparaben,Ethylparaben, Propylparaben, pH adjusted to 5.5 D Products of theinvention 0.01-10%

Formulation 12b:

A Water qsp 100 Butylene Glycol 2 Glycerol 3 Polyacrylamide,Isoparaffin, 2.8 Laureth-7 B Butylene Glycol, 2 Methylparaben,Ethylparaben, Propylparaben; Phenoxyethanol, 2 Methylparaben,Propylparaben, Butylparaben, Ethylparaben Butylene Glycol 0.5 D Productsof the invention 0.01-10%

Formulation 12c:

A Carbomer 0.50 Propylene Glycol 3 Glycerol 5 Water qsp 100 B OctylCocoate 5 Bisabolol 0.30 Dimethicone 0.30 C Sodium Hydroxide 1.60 DPhenoxyethanol, 0.50 Methylparaben, Propylparaben, Butylparaben,Ethylparaben E Perfume 0.30 F Products of the invention 0.01-10%

Example 13 Use of the Products of the Invention in a Water-in-Oil TypeFormulation

A PEG 30 - 3 dipolyhydroxystearate Capric Triglycerides 3 CetearylOctanoate 4 Dibutyl Adipate 3 Grape Seed Oil 1.5 Jojoba Oil 1.5Phenoxyethanol, 0.5 Methylparaben, Propylparaben, Butylparaben,Ethylparaben B Glycerol 3 Butylene Glycol 3 Magnesium Sulphate 0.5 EDTA0.05 water qsp 100 C Cyclomethicone 1 Dimethicone 1 D Perfume 0.3 EProducts of the invention 0.01-10%

Example 14 Use of the Products of the Invention in a Formulation ofShampoo or Shower Gel Type

A Xantham Gum 0.8 Water qsp 100 B Butylene Glycol, 0.5 Methylparaben,Ethylparaben, Propylparaben Phenoxyethanol, 0.5 Methylparaben,Propylparaben, Butylparaben, Ethylparaben C Citric acid 0.8 D SodiumLaureth Sulphate 40.0  E Product of the invention 0.01-10%

Example 15 Use of the Products of the Invention in a Formulation ofLipstick and Other Anhydrous Product Type

A Mineral Wax 17.0 Isostearyl Isostearate 31.5 Propylene GlycolDipelargonate 2.6 Propylene Glycol Isostearate 1.7 PEG 8 Beeswax 3.0Hydrogenated Palm Kernel Oil 3.4 Glycerides, Hydrogenated PalmGlycerides Lanolin Oil 3.4 Sesame Oil 1.7 Cetyl Lactate 1.7 Mineral Oil,Lanolin Alcohol 3.0 B Castor Oil qsp 100 Titanium Dioxide 3.9 CI 15850:10.616 CI 45410:1 0.256 CI 19140:1 0.048 CI 77491 2.048 C Products of theinvention 0.01-5%

Example 16 Use of the Products of the Invention in a Formulation ofAqueous Gels (Eyeliners, Slimmers, Etc.)

A water qsp 100 Carbomer 0.5 Butylene Glycol 15 Phenoxyethanol,Methylparaben, 0.5 Propylparaben, Butylparaben, Ethylparaben B Productsof the invention 0.01-10%

Example 17 Preparation of Pharmaceutical Formulations Containing LOXLFormulation 17a: Preparation of Tablets

A Excipients In g, per tablet Lactose 0.359 Sucrose 0.240 B Extract ofLOXL* 0.001-0.1 *The extract of LOXL is obtained for example accordingto the method of extraction described in Example 2, followed by a dryingstep.

Formulation 17b: Preparation of an Ointment

A Excipients Low density polyethylene 5.5 Liquid paraffin qsp 100 BExtract of LOXL* 0.001-0.1 *The extract of LOXL is obtained for exampleaccording to the method of extraction described in Example 2, optionallyfollowed by a drying step.

Formulation 17c: Preparation of an Injectable Formula

A Excipient Saline isotonic solution 5 ml B Extract of LOXL* 0.001-0.1 g*The extract of LOXL is obtained for example according to the method ofextraction described in Example 2, followed by a drying step.

Phase A and Phase B are packaged in separate ampoules and are mixedbefore use.

Example 18 Evaluation of the Cosmetic Acceptance of a PreparationContaining the Subject of the Invention

Toxicology tests were carried out on the compounds obtained according toExamples 10 and 11 incorporated at 10% in a 0.5% xanthan gum, by anocular evaluation, in the rabbit, by the study of the absence ofabnormal toxicity by single oral administration in the rat and by, thestudy of the sensitizing power in the guinea pig.

Evaluation of the Primary Irritation of the Skin in the Rabbit:

The preparations described above were applied without dilution at thedose of 0.5 ml on the skin of 3 rabbits according to the methodrecommended by the OECD in relation to the study of <<the acuteirritant/corrosive effect on the skin>>.

The products are classed according to the criteria defined in theDecision of Jan. 2, 1982 published in the Official Journal of the FrenchRepublic (the “JORF”) of 21/02/82.

The results of these tests have enabled concluding that the preparationcontaining the compound obtained according to Example 11 was classed asnon-irritant for the skin.

Evaluation of the Ocular Irritation in the Rabbit:

The preparations described above were instilled pure and in one batch atthe rate of 0.1 ml in the eye of three rabbits according to the methodrecommended by the directive of the OECD NO. 405 of Feb. 24, 1987, inrelation to the study of “the acute irritant/corrosive effect on theeyes”.

The results of this test enable concluding that the preparations can beconsidered as non-irritant for the eyes, in the sense of the Directive91/326 EEC, used pure or without dilution.

Test on the Absence of Abnormal Toxicity by Single Oral Administrationin the Rat:

The preparations described were administered in one batch orally at thedose of 5 g/Kg of body weight, to 5 male rats and 5 female rats of aprotocol inspired from the Directive of the OECD No. 401 of Feb. 24,1987 and adapted to cosmetic products.

The LD0 and LD50 are found to be greater than 5,000 mg/Kg. Thepreparations tested are therefore not classed amongst the preparationswhich are dangerous by ingestion.

Evaluation of the Skin Sensitization Potential in the Guinea Pig:

The preparations described are subjected to the maximization testdescribed by Magnusson and Kligmann, a protocol which is in agreementwith the directive line No. 406 of the OECD.

The preparations are classed as non-sensitizing by contact with theskin.

Precisions on the Sequences which are Described:

Sequence ID No 1: is the peptide sequence of the human protein LOXL.

Sequence ID No 2: is the sequence of nucleotides of the cDNA encodingthe human protein LOXL described in sequence ID No 1.

Sequence ID No 3: is the sequence of nucleotides of the cDNA encodingthe promoter of the human gene encoding the protein LOXL described insequence ID No 1.

Sequence ID No 4: is the peptide sequence of the human proteintropoelastin.

Sequence ID No 5: is the sequence of nucleotides of the cDNA encodingthe human protein tropoelastin described in sequence ID No 4.

Sequence ID No 6: is the peptide sequence of the human protein LOX.

Sequence ID No 7: is the sequence of nucleotides of the cDNA encodingthe human protein LOX described in sequence ID No 6.

For the Double Strand DNA Probes:

Sequence ID No 8: is a sense primer of the DNA encoding the humanprotein LOXL described in sequence ID No 1

Sequence ID No 9: is an antisense primer of the DNA encoding the humanprotein LOXL described in sequence ID No 1.

Sequence ID No 10: is a sense primer of the DNA encoding the humanprotein tropoelastin described in sequence ID No 4.

Sequence ID No 11: is an antisense primer of the DNA encoding the humanprotein tropoelastin described in sequence ID No 4.

Sequence ID No 12: is a sense primer of the DNA encoding the humanprotein LOX described in sequence ID No 6.

Sequence ID No 13: is an antisense primer of the DNA encoding the humanprotein LOX described in sequence ID No 6.

Sequence ID No 14: is a sense primer of the DNA encoding the humanprotein collagen I α1L.

Sequence ID No 15: is an antisense primer of the DNA encoding the humanprotein collagen I α1L.

For the fusion genes GST:

Sequence ID No 16: is a sense primer of the DNA of the fusion gene GSTS355-D415.

Sequence ID No 17: is an antisense primer of the DNA of the fusion geneGST S355-D415.

Sequence ID No 18: is a sense primer of the DNA of the fusion gene GSTG128-L212.

Sequence ID No 19: is an antisense primer of the DNA of the fusion geneGST G128-L212.

Sequence ID No 20: is a sense primer of the DNA of the fusion gene GSTV228-S279.

Sequence ID No 21: is an antisense primer of the DNA of the fusion geneGST V228-S279.

Sequence ID No 22: is a sense primer of the DNA of the fusion gene GSTD306-N373.

Sequence ID No 23: is an antisense primer of the DNA of the fusion geneGST D306-N373.

For the PCR primers:

Sequence ID No 24: is a sense primer for the RT-PCR of the mRNA encodingthe human protein tropoelastin described in sequence ID No 4.

Sequence ID No 25: is an antisense primer for the RT-PCR of the mRNAencoding the human protein tropoelastin described in sequence ID No 4.

Sequence ID No 26: is a sense primer for the RT-PCR of the mRNA encodingthe human protein LOXL described in sequence ID No 1.

Sequence ID No 27: is an antisense primer of the sequence of the mRNAencoding the human protein LOXL described in sequence ID No 1.

Sequence ID No 28: is a sense primer for the RT-PCR of the mRNA encodingthe human protein LOX described in sequence ID No 6.

Sequence ID No 29: is an antisense primer for the RT-PCR of the mRNAencoding the human protein LOX described in sequence ID No 6.

Sequence ID No 30: is a sense primer for the RT-PCR of the mRNA encodingthe human protein actin.

Sequence ID No 31: is an antisense primer for the RT-PCR of the mRNAencoding the human protein actin.

1. A composition for stimulating the formation of tissue elastic fibers,comprising the isoform of lysyl oxidase LOXL having the amino acidsequence of SEQ ID NO: 1, or of an homologous or essentially homologousform thereof.
 2. A composition for stimulating the formation of elasticfibers, comprising a substance stimulating LOXL.
 3. The composition ofclaim 2, wherein the stimulating of LOXL is selected from the groupconsisting of stimulating the activity of LOXL, stimulating theexpression of a sequence of nucleotide encoding LOXL, and stimulatingthe expression of a sequence of peptides constituting a fraction ofLOXL.
 4. The composition of claim 1, wherein the composition furthercomprises a second substance stimulating the expression of the proteinelastin.
 5. The composition of claim 4, wherein the second substance isthe substance stimulating LOXL.
 6. The composition of claim 2, whereinthe substance comprises a region which fixes to a part of the nucleotidesequence of the promoter of the human LOXL gene (SEQ ID NO: 3) or of anhomologous or essentially homologous form thereof.
 7. The composition ofclaim 2, wherein the substance modulates the expression of the proteinwhich fixes to a part of the sequence of nucleotides of the promoter ofthe human LOXL gene (SEQ ID NO: 3).
 8. The composition of claim 2,wherein the substance is selected from the group consisting of dill,currant, cardamon, black radish, small holly, cinnamon, lacticbacteria-based fermentations, oats, potato, silk, Asea foetida gum,ethyl hexenoate and its derivatives, methyl butyrate and itsderivatives, and ethyl decadienoate and its derivatives.
 9. A cosmeticcomposition, comprising the composition of claim 1, in admixture with acosmetically acceptable excipient.
 10. A cosmetic composition,comprising the composition of claim 2, in admixture with a cosmeticallyacceptable excipient.
 11. A neutraceutical composition, comprising thecomposition of claim 1, in admixture with an excipient acceptable forfood.
 12. A neutraceutical composition, comprising the composition ofclaim 2, in admixture with an excipient acceptable for food.
 13. Apharmaceutical composition, comprising the composition of claim 1, inadmixture with a pharmaceutically acceptable excipient.
 14. Apharmaceutical composition, comprising the composition of claim 2, inadmixture with a pharmaceutically acceptable excipient.
 15. A method ofcosmetic care, comprising delivering to a person the composition ofclaim
 9. 16. A method of cosmetic care, comprising delivering to aperson the composition of claim
 10. 17. The method of cosmetic care ofclaim 15, wherein the cosmetic care is selected from the groupconsisting of combating against the loosening of the tissues, againstthe loosening of the tissues during ageing, combating against theloosening of tissues during solar exposures, densifying theextracellular matrix, firming up the subcutaneous tissues, reducing skinwrinkles, slowing down the appearance of anti-wrinkles effect, improvingthe quality of scar tissue, improving the appearance of scars, improvingthe appearance and the quality of dystrophic, improving the appearanceand the quality of keloid scars, and combating against stretch marks.18. The method of cosmetic care of claim 16, wherein the cosmetic careis selected from the group consisting of combating against the looseningof the tissues, against the loosening of the tissues during ageing,combating against the loosening of tissues during solar exposures,densifying the extracellular matrix, firming up the subcutaneoustissues, reducing skin wrinkles, slowing down the appearance ofanti-wrinkles effect, improving the quality of scar tissue, improvingthe appearance of scars, improving the appearance and the quality ofdystrophic, improving the appearance and the quality of keloid scars,and combating against stretch marks.
 19. A screening method forscreening for a substance stimulating the isoform of lysyl oxidase LOXL,wherein the method comprises the following steps: placing a potentiallyactive substance in contact with LOXL, and analyzing the activity ofLOXL, with the aim of identifying whether the potentially activesubstance stimulates the activity of LOXL.
 20. A screening method forscreening a substance stimulating the expression of LOXL or of anhomologous or essentially homologous form thereof, the methodcomprising: placing a potentially active substance in contact with cellscapable of expressing the isoform LOXL of the protein lysyl oxidase(LOXL) or of an homologous or essentially homologous form thereof, andanalyzing the activity or the expression of LOXL or of an homologous oressentially homologous form thereof, with the aim of identifying whetherthe potentially active substance stimulates the expression of LOXL or ofan homologous or essentially homologous form thereof.
 21. The screeningmethod of claim 20, wherein the analysis of the expression of LOXLcomprises an analysis selected from the group consisting of analyzingthe expression of at least one nucleotide sequence encoding the proteinLOXL, and analyzing the expression of a peptide sequence constituting ofa peptide fraction of the protein LOXL.
 22. The screening method ofclaim 20, wherein the analysis of the expression of LOXL is carried outby a method selecting from the group consisting of qualitative analysisof the expression of at least one part of nucleotide sequence encodingLOXL, and quantitative analysis of the expression of at least one partof nucleotide sequence encoding LOXL.
 23. The screening method of claim21, wherein the nucleotide sequence is the cDNA of LOXL being defined bythe sequence ID No 2, which is complementary to the mRNA encoding LOXL.24. The screening method of claim 21, wherein the analysis of theexpression of LOXL uses a reverse transcription polymerase chainreaction (RT-PCR) which comprises the use of primers hybridizing with atleast one part of the nucleotide sequence of the complementary DNAencoding LOXL (SEQ ID NO: 2), to amplify at least one part of thenucleotide sequence encoding LOXL.
 25. The screening method of claim 20,wherein the method comprises a step of locating the expression of LOXLwhich is carried out on a reconstructed skin model or on a model basedon biopsies, by a method selected from the group consisting of in situin situ hybridization of at least one part of a nucleotide sequenceencoding LOXL, and immuno-detection using at least one specific antibodyto LOXL.
 26. The screening method of claim 20, wherein the methodcomprises comparing the expression of LOXL with the expression of LOXLexpressed in a control which does not comprise the potentially activesubstance.
 27. The screening method of claim 20, wherein the potentiallyactive substance is in contact with living cells, the living cellsselected from the group consisting of fibroblasts, fibroblasts fromnormal human skin, fibroblasts originating from the foreskin,fibroblasts originating from a skin of an adult subject, epithelialcells, keratinocytes, keratinocytes originating from normal human skin,keratinocytes originating from the foreskin, and keratinocytesoriginating from a skin of an adult subject.
 28. The screening method ofclaim 20, wherein the potentially active substance is in contact withliving cells, the living cells originating from at least one skin havinga particular location, the location being the face, the abdomen, thebreasts, a zone which has scars or stretch marks and the living cellsbeing able to be characterized as aged or as exposed to sun's radiationor not.
 29. The screening method of claim 28, comprising the use of amodel selected from the group consisting of a reconstructed skin model,a model based on biopsies, a dermis model comprising fibroblasts, and anepidermis model comprising keratinocytes, for placing in contact thepotentially active substance with the cells.
 30. The screening method ofclaim 20, wherein said method comprises an analysis selected from thegroup consisting of analyzing the expression of the sequence at least ofthe protein elastin and analyzing the expression of a nucleotidesequence encoding the protein elastin.
 31. The screening method of claim20, wherein said method comprises immuno-detecting the expression of theprotein LOXL, with the aim of performing the traceability ofneo-elastogenesis.
 32. The screening method of claim 31, wherein theimmuno-detection is carried out on tissue selected from the groupconsisting of epithelial tissues and connective tissues. 33-34.(canceled)
 35. A method of treatment of a disorder associated with theenzymatic activity of the isoform of the protein lysyl oxidase LOXL,comprising administering to a subject in need thereof a therapeuticallyeffective amount of a composition comprising the protein lysyl oxidaseLOXL or an homologous or essentially homologous form thereof.
 36. Amethod of treatment of a disorder associated with the enzymatic activityof the isoform of the protein lysyl oxidase LOXL, comprisingadministering to a subject in need thereof a therapeutically effectiveamount of a composition comprising a substance stimulating the proteinlysyl oxidase LOXL, the stimulation being selected from the groupconsisting of stimulating the enzymatic activity of the protein lysyloxidase LOXL, and stimulating the expression of the protein lysyloxidase LOXL.
 37. The method of claim 35, wherein the treatment isselected from the group consisting of combating against the loosening ofthe tissues, densifying the extra cellular matrix, firming up thesubcutaneous tissues, reducing skin wrinkles, anti-wrinkles effect,improving the quality of scar tissue, improving the quality of theappearance of scars, improving the quality of the dystrophic scars,improving the appearance of dystrophic scars, improving the quality ofkeloid scars, improving the appearance of keloid scars, and combatingagainst stretch marks.
 38. A method of stimulating the formation of skinelastic fibers comprising applying to the skin an effective amount of asubstance which stimulates the enzymatic activity or expression of thelysyl oxidase isoform LOXL.
 39. The method of claim 38, wherein thelysyl oxidase isoform LOXL has the amino acid sequence of SEQ ID NO: 1.40. The method of claim 38, wherein the lysyl oxidase isoform LOXLstimulates the expression of the protein elastin.
 41. The method ofclaim 38, wherein the substance comprises a region which fixes to atleast one part of the sequence of nucleotides of the lysyl oxidaseisoform LOXL promoter of SEQ ID NO:
 3. 42. The method of claim 38,wherein the substance modulates the expression of a protein which fixesto a part of the sequence of nucleotides encoding the lysyl oxidaseisoform LOXL promoter of SEQ ID NO:
 3. 43. The method of claim 38,wherein the substance is selected from the group consisting of anextract of dill, an extract of cardamon, an extract of currant, anextract of black radish, an extract of small holly, an extract ofcinnamon, a lactic bacteria-based fermentation, an extract of oats, anextract of potato, a silk protein, Asea foetida gum, ethyl hexenoate,methyl butyrate, ethyl decadienoate, and combinations thereof.
 44. Themethod of claim 43, wherein the effective amount of the substance isbetween 0.1% and 5% (v/v).
 45. The method of claim 38, wherein thestimulation of the skin elastic fibers provides a cosmetic benefit tothe skin.
 46. The method of claim 45, wherein the cosmetic benefit iscombating against the loosening of tissues, for densifying theextracellular matrix, for firming up the subcutaneous tissues, forreducing skin wrinkles, for exerting an anti-wrinkle effect, forimproving the appearance of scars, or for combating against stretchmarks.